12 medium to large cremini mushrooms, rinsed clean of grit
1 tablespoon olive oil, plus more to grease the grill
1 small yellow bell pepper, diced
1 red jalapeño or red fresno chile pepper, diced (See Recipe Note)
1/2 poblano pepper, diced
1/2 sweet onion, diced
1 cup grated Gruyère cheese
1/2 cup panko breadcrumbs
Salt and pepper
Preheat a grill to medium-high heat. Use a small paring knife to cut the stem off of each mushroom, then hollow out each mushroom a bit to create a cavity for stuffing. Be careful not to cut through the mushroom.
In a medium skillet, heat a tablespoon of oil over medium heat. Add the diced peppers and onion, and season with a pinch of salt and pepper. Cook the vegetables until they soften, 4 to 5 minutes. Remove the vegetables from the heat and let cool briefly. Stir in the grated cheese.
In a small skillet, toast breadcrumbs over low heat until they are lightly browned.
Stuff mushrooms with the pepper and cheese mixture. Sprinkle breadcrumbs on top of each mushroom.
Lightly oil a paper towel or clean rag with olive oil and brush onto the hot grill. Carefully place the stuffed mushrooms on the hot grill. Cover and let the mushrooms cook for 5 to 6 minutes until the cheese is melted and the mushrooms are just cooked through. Serve while warm.
You can get creative with the filling for these. Really anything that's diced relatively small (and can be mixed with cheese) will probably work well in these.
A red jalapeño pepper is one that has ripened beyond green and become red. If this isn't available, you can substitute red fresno chile peppers.