Make-Ahead Grilled Summer Vegetable Gratin with Parmesan & Lemon — Labor Day Steak Side

How to Make Make-Ahead Grilled Summer Vegetable Gratin with Parmesan & Lemon — Labor Day Steak Side

1. 1

   Step 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.)

   For this step

   • 3 medium (total)Zucchini and yellow squash (combined)
   • 1 mediumEggplant
   • 2 mediumSweet bell peppers (red/yellow)
   
2. 2

   Step 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.

   For this step

   • 1 cupCrème fraîche or full-fat Greek yogurt
   • 3/4 cupGrated Parmesan cheese
   • 1 medium (zest + 1 tbsp juice)Lemon (zest + 1 tbsp juice)
   
3. 3

   Step 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.

   For this step

   • 1 cupPanko breadcrumbs
   • 2 tbspUnsalted butter (melted)
   
4. 4

   Step 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. 5

   Step 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. 6

   Step 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.
   

1. 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. 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. 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. 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. 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 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.