# Make-Ahead Grilled Summer Vegetable Gratin with Parmesan & Lemon — Labor Day Steak Side > Charred summer zucchini, yellow squash, eggplant and sweet peppers are layered with a light lemon-parmesan cream, topped with crisp panko and broiled until golden. Assemble ahead for an effortless Labour Day steak side and finish on the grill or under the oven broiler for a smoky, golden topping. Canonical URL: https://www.topshelf.recipes/recipes/make-ahead-grilled-summer-vegetable-gratin-parmesan-lemon-labour-day-steak-side ## Author Jake Woods https://www.topshelf.recipes/chef/jake-woods Published: July 31, 2026 Last Updated: September 3, 2026 ## About This Recipe This gratin is built on contrasts: summer vegetables cooked over high heat until their skins blacken and sugars concentrate, then layered with a lemony, slightly salty Parmesan cream and finished with a golden panko crust. The char from the grill gives each slice a smoky backbone that stands up to steak, while the crème fraîche (or full-fat Greek yogurt) lends a cool, tangy counterpoint so the dish never feels heavy. Texturally it’s generous—silky eggplant, tender squash ribbons and crisp-topped crumbs—but the bright lemon keeps every bite lively. What makes this version work for holiday cookouts is its make-ahead logic. You do the labor (and the smoky char) when you have time, refrigerate the assembled pan, and then finish on the grill or under the broiler for a last-minute showpiece with minimal fuss. It’s tailor-made for hosts who want a vegetable-forward side that looks and tastes deliberate next to a simply grilled steak, and the panko-Parmesan topping gives you that irresistible crunch that crowds will fight over. ## Recipe Information - Prep Time: 45 minutes - Cook Time: 25 minutes - Total Time: 70 minutes - Servings: 6 - Difficulty: Medium - Category: Dinner ## Ingredients ### Slice and char the vegetables - 3 medium (total) Zucchini and yellow squash (combined) - 1 medium Eggplant - 2 medium Sweet bell peppers (red/yellow) - 3 tbsp Extra-virgin olive oil - 1 tsp salt + 1/2 tsp pepper (approx) Kosher salt and freshly ground black pepper ### Make the lemon-parmesan cream - 1 cup Crème fraîche or full-fat Greek yogurt - 3/4 cup Grated Parmesan cheese - 1 medium (zest + 1 tbsp juice) Lemon (zest + 1 tbsp juice) ### Prepare the panko topping - 1 cup Panko breadcrumbs - 2 tbsp Unsalted butter (melted) ## Ingredient Guide ### Crème fraîche A cultured cream from France with a high fat content that is richer and less tangy than sour cream; it’s smooth and mildly tangy with a lightly nutty dairy aroma and holds up when warmed. You’ll find it in the refrigerated dairy section of large supermarkets, specialty grocery stores, or international markets. Good substitutes are full-fat Greek yogurt (thicker and tangier) or a mix of heavy cream and a small amount of cultured buttermilk left to thicken, though flavor and stability will differ slightly. ### Panko breadcrumbs Panko are Japanese-style breadcrumbs made from crustless white bread that are dried into large, airy flakes; they produce a very light, extra-crispy crust compared with regular breadcrumbs. Look for them in the Asian foods aisle or breading/cracker section of most supermarkets and Asian markets. If you can’t find panko, use regular breadcrumbs, crushed cornflakes, or pulse crustless bread into coarse crumbs for a similar effect, though texture will not be identical. ## Instructions ### 1. Slice and char the vegetables Slice zucchini and yellow squash lengthwise into 1/4" slices, cut eggplant into 1/2" rounds, and quarter the peppers, removing stems and seeds. Toss all vegetables with 2 tbsp olive oil and a generous pinch of the kosher salt and black pepper. Grill over high heat (or use a ridged grill pan) in batches, 3–5 minutes per side, until deeply charred and tender; set aside to cool slightly. (If using a hot gas grill, you can place peeled pepper halves skin-side down until blistered and charred.) ### 2. Make the lemon-parmesan cream Whisk together the crème fraîche (or Greek yogurt), grated Parmesan (reserve 2 tbsp for topping), lemon zest and 1 tbsp lemon juice with the remaining pinch of salt and pepper until smooth. Taste and adjust acidity or salt — the mixture should be bright but not overpoweringly tart. This light cream binds the layers and keeps the gratin from feeling heavy. ### 3. Prepare the panko topping Mix the panko breadcrumbs with the melted butter, remaining reserved Parmesan, and 1 tbsp olive oil until moistened and evenly coated. This will give a golden, crisp finish under the broiler or on the grill. Set aside until assembly. ### 4. Assemble the gratin (make-ahead) Spread a thin layer of lemon-parmesan cream in the bottom of a 9x13" (or equivalent shallow) ovenproof baking dish. Layer half the charred vegetables, dollop and spread half the cream, then repeat with remaining vegetables and cream. Sprinkle the panko mixture evenly over the top. Cover tightly and refrigerate for 1–24 hours — the gratin holds well overnight, making this an ideal make-ahead Labour Day side. ### 5. Finish on the grill or in the oven From chilled: to reheat on the grill, preheat grill to medium (about 375–400°F / 190–205°C). Place dish on the cooler part of the grate, cover and heat 10–12 minutes until warmed through, then move over direct medium-high heat (or increase grill temp) and cook 3–6 minutes with lid closed until topping is crisp and golden — watch closely to avoid burning. For oven: preheat to 375°F (190°C), cover with foil and bake 20–25 minutes until hot; remove foil and broil 2–4 minutes until topping is golden. Let rest 5 minutes before serving. ### 6. Serve and dairy-free shortcut Serve hot alongside grilled steak—ladle or slice into 6 portions (about 1 cup each). Shortcut dairy-free variation: swap the crème fraîche and Parmesan for 1 cup unsweetened dairy-free yogurt or mayo plus 3 tbsp nutritional yeast; skip the butter in the panko and toss crumbs with 2 tbsp olive oil instead. Grill finish times are the same for the dairy-free version. ## Nutrition Estimated nutrition per serving (about ½ cup): - Calories: 311 kcal - Protein: 9.2 g - Carbohydrates: 26.3 g - Fat: 19.3 g - Saturated Fat: 8.1 g - Trans Fat: 0.1 g - Fiber: 4.4 g - Sugar: 6.7 g - Added Sugars: 0.4 g - Cholesterol: 40 mg - Sodium: 1413 mg - Potassium: 222 mg - Calcium: 223 mg - Iron: 1.5 mg - Vitamin D: 0.1 mcg ## Tips ### Salt eggplant early Salt thick eggplant rounds 20–30 minutes before grilling and blot away moisture to reduce bitterness and prevent sogginess during assembly. ### Char in manageable batches Work in batches so the grill stays hot—crowding cools the grates and produces steaming instead of proper charring. ### Protect the panko topping If finishing on the grill, set the dish on the cooler side first to warm through, then move it briefly over direct heat to brown so the crumbs crisp without burning. ### Keep cream bright Taste the lemon-Parmesan mixture before assembly and err on the side of less acid; chilling mutes citrus, so it should be lively but not sharp. ### Toast panko first For extra depth, toast the panko in a skillet with the butter and oil until lightly golden before topping—this prevents raw crumbiness after baking. ## Variations and Substitutions ### Tomato and basil Layer thin slices of ripe tomato and a handful of chiffonaded basil between the charred vegetables for a Caprese-inspired lift; omit some lemon to avoid competing acidity. ### Smoky harissa twist Stir 1–2 tbsp mild harissa into the cream and add a tablespoon to the panko for a warm, smoky heat that pairs beautifully with grilled steak. ### Cheese-forward gratin Swap half the Parmesan for grated Gruyère or aged fontina for a more indulgent, melty interior while keeping the panko crisp on top. ### Vegan/dairy-free option Use unsweetened dairy-free yogurt or blended silken tofu plus 3 tbsp nutritional yeast for umami, and toss panko with olive oil instead of butter to keep the topping crisp. ## Notes This gratin is designed to be mostly done ahead so you can focus on the steak and guests. The bright lemon-parmesan cream keeps it feeling fresh, while the charred vegetables echo grill-smoke flavors. ### Storage and Make-Ahead Keep leftovers covered in the refrigerator for up to 3–4 days; the topping will soften a bit but the flavors meld nicely overnight. To reheat, warm in a 350°F (175°C) oven until heated through and then broil or place briefly over direct grill heat to re-crisp the panko—avoid microwaving if you want to preserve texture. You can freeze the gratin (without the panko topping) for up to 2 months; thaw thoroughly, add fresh crumbs and finish under the broiler. ### Serving Suggestions Serve this gratin alongside a simply seasoned, high-heat grilled steak—flank or ribeye work particularly well—so the gratin’s brightness cuts through the meat’s richness. Offer a crisp, herb-forward salad (think arugula with lemon and shaved fennel) and grilled corn for a full summer spread. For drinks, a chilled Provençal rosé or a medium-bodied Grenache pairs nicely with the smoky vegetables and Parmesan. ## Frequently Asked Questions ### My vegetables released a lot of water — how can I prevent a soggy gratin? Salt eggplant ahead of time and pat dry, don't overcrowd the grill to avoid steaming, and allow grilled vegetables to cool on a rack so excess moisture drains before layering. ### Can I roast the vegetables instead of grilling? Yes — roast at 450°F on a rimmed sheet until deeply browned and tender (about 20–30 minutes), flipping once; you’ll miss some smokiness but the caramelization still gives great flavor. ### How far ahead can I assemble the gratin? You can assemble and refrigerate the covered dish for 24 hours; beyond that the topping may soften further and vegetables will continue to shed moisture. ### Is this dish freezer-friendly? It freezes best without the panko topping; store covered for up to 2 months, thaw overnight, add fresh crumbs, and reheat/broil to crisp. ### Why use crème fraîche instead of mayonnaise or heavy cream? Crème fraîche provides a tangy richness and stabilizes when warmed, so the gratin stays creamy without becoming greasy like mayo or overly heavy like heavy cream. ## Related Recipes and Guides - [Classic Bacon Carbonara](https://www.topshelf.recipes/recipes/classic-bacon-carbonara) - [Al Pastor Tacos](https://www.topshelf.recipes/recipes/al-pastor-tacos) - [Jamaican Jerk Chicken Marinade for Smoking or Grilling](https://www.topshelf.recipes/recipes/jamaican-jerk-chicken-smoking) - [Air Fryer Chicken Sliders](https://www.topshelf.recipes/recipes/air-fryer-chicken-sliders-sticky-glaze) - [Smoked Chicken Burger](https://www.topshelf.recipes/recipes/smoked-chicken-burger-sweet-savory-onion-jam) - [Beer-Can Grilled Whole Chicken](https://www.topshelf.recipes/recipes/beer-can-grilled-whole-chicken) - [End-of-Summer Vegetable Grill Roundup](https://www.topshelf.recipes/articles/end-of-summer-vegetable-grill-roundup) - [Trending Labor Day Steak Finishes](https://www.topshelf.recipes/articles/trending-labor-day-steak-finishes) - [7 Day Labor Day Drink Prep](https://www.topshelf.recipes/articles/7-day-labor-day-drink-prep)