Grilled King Oyster Mushroom 'Scallops' with Lemon-Caper Brown Butter on Crispy Sourdough

How to Make Grilled King Oyster Mushroom 'Scallops' with Lemon-Caper Brown Butter on Crispy Sourdough

1. 1

   Step 1: Slice and marinate the mushrooms

   Trim ends of king oyster mushrooms and slice crosswise into thick 1" rounds (about 8–10 medallions). In a bowl whisk olive oil, lemon juice, soy sauce and garlic powder; toss mushrooms to coat and let sit 10–15 minutes while you preheat the grill to high. (Season lightly with salt and pepper to taste if desired.)

   For this step

   • 12 ozKing oyster mushrooms (thick slices)
   • 3 tbspExtra-virgin olive oil
   • 1 tbspFresh lemon juice
   • 1 tbspLow-sodium soy sauce (or tamari)
   • 1/2 tspGarlic powder
   
2. 2

   Step 2: Dust and grill for a scallop-like crust

   Preheat your grill for direct high heat (450–500°F / 230–260°C). Lightly dust both sides of the marinated rounds with cornstarch, brush sourdough rounds and mushroom medallions with a little additional olive oil, and oil the grates. Place mushrooms on the hottest part of the grill and sear 3–4 minutes per side without moving until deep caramelization forms; press gently with a spatula for full contact and rotate 90° halfway through each side for a crosshatch crust. Meanwhile char sourdough 30–45 seconds per side until crisp and marked.

   For this step

   • 2 tspCornstarch (light dusting to encourage crust)
   • 8 slicesSourdough rounds (sliced to 2" rounds or use small slices)
   
3. 3

   Step 3: Make the lemon-caper brown butter

   While the mushrooms grill, melt butter in a small stainless skillet over medium heat and cook until it foams and turns a golden-brown nutty aroma (watch closely — 2–4 minutes). Remove from heat and stir in the rinsed capers and 1 tsp fresh lemon zest plus 1 tbsp lemon juice for brightness; return to very low heat just to warm the sauce, then remove so it doesn't overbrown.

   For this step

   • 4 tbspUnsalted butter
   • 2 tbspCapers (rinsed and drained)
   
4. 4

   Step 4: Finish the mushrooms in the brown butter

   Transfer the hot grilled mushroom rounds into the skillet with the brown butter and toss or spoon the sauce over them 20–30 seconds to glaze and absorb flavor (do this in batches to avoid crowding). This quick finishing step builds extra gloss and flavor without steaming the crust.

   For this step

   • 1 cupMicrogreens (for garnish)
   
5. 5

   Step 5: Assemble and serve party-friendly bites

   Place one grilled mushroom 'scallop' on each charred sourdough round, spoon a little lemon-caper brown butter over the top, and finish with a small cluster of microgreens. For party service, arrange on a platter with toothpicks, keep warm on a sheet pan in a 200°F (95°C) oven for up to 20 minutes, and make the brown butter ahead to rewarm gently just before serving.
   

1. Trim ends of king oyster mushrooms and slice crosswise into thick 1" rounds (about 8–10 medallions). In a bowl whisk olive oil, lemon juice, soy sauce and garlic powder; toss mushrooms to coat and let sit 10–15 minutes while you preheat the grill to high. (Season lightly with salt and pepper to taste if desired.)
2. Preheat your grill for direct high heat (450–500°F / 230–260°C). Lightly dust both sides of the marinated rounds with cornstarch, brush sourdough rounds and mushroom medallions with a little additional olive oil, and oil the grates. Place mushrooms on the hottest part of the grill and sear 3–4 minutes per side without moving until deep caramelization forms; press gently with a spatula for full contact and rotate 90° halfway through each side for a crosshatch crust. Meanwhile char sourdough 30–45 seconds per side until crisp and marked.
3. While the mushrooms grill, melt butter in a small stainless skillet over medium heat and cook until it foams and turns a golden-brown nutty aroma (watch closely — 2–4 minutes). Remove from heat and stir in the rinsed capers and 1 tsp fresh lemon zest plus 1 tbsp lemon juice for brightness; return to very low heat just to warm the sauce, then remove so it doesn't overbrown.
4. Transfer the hot grilled mushroom rounds into the skillet with the brown butter and toss or spoon the sauce over them 20–30 seconds to glaze and absorb flavor (do this in batches to avoid crowding). This quick finishing step builds extra gloss and flavor without steaming the crust.
5. Place one grilled mushroom 'scallop' on each charred sourdough round, spoon a little lemon-caper brown butter over the top, and finish with a small cluster of microgreens. For party service, arrange on a platter with toothpicks, keep warm on a sheet pan in a 200°F (95°C) oven for up to 20 minutes, and make the brown butter ahead to rewarm gently just before serving.