3 tablespoons shredded Gruyere cheese or aged extra sharp cheddar (swap for nutritional yeast and sprinkle on top for Whole30)
Preheat oven to 400 degrees.
Remove stems from mushrooms and combine with the garlic, red bell pepper, jalepeño pepper (optional) into a manual food chopperor pulse a few times in a food processor.
Heat the oil in a medium-sized skillet over medium heat; add the mushroom mixture and sauté for 3 to 4 minutes, until mushrooms soften. Season with salt to taste. Transfer mushrooms to a medium-sized mixing bowl.
Add chopped parsley and combine.
Place the mushrooms onto a prepared baking sheet. Using 2 spoons, carefully scoop the mixture into the mushrooms and bake for 15 minutes.
Carefully remove the hot baking sheet from the over, top with cheese and return to the oven for 2-3 minutes until the cheese has melted. You can also broil on low for 2-3 minutes.