Humble white button mushrooms get transformed into tasty mushroom cap appetizers! Even though mushrooms appear to be humble, in reality they are true superstars packed with nutrients that heal and nourish. This appetizer is one of many ways to enjoy this superfood.
Preheat oven to 400 degrees F.
Remove stems from mushrooms and reserve.
Place mushroom caps with hole side up on a baking sheet lined with parchment paper.
Bake for 8–9 minutes until the caps have collected some juice from the mushrooms.
Remove and let cool a little.
Soak up the juices with a cloth or paper towel, or tip the caps upside down, discarding the juices.
For the filling, mince the mushroom stems and combine in a bowl with all the remaining ingredients (except the reserved breadcrumbs for the topping).
Work the mixture until it starts to come together, binding a little when pressed. For a tighter mixture, add a little more tomato paste.
Spoon filling into mushroom caps.
Sprinkle the reserved breadcrumbs on top, pressing them lightly onto the filling.
Bake at 400 degrees F for 10–12 minutes until lightly browned.
Remove and serve.