oven at 400

in medium skillet over medium heat, heat oil

add shallots and scallion and sauteed until softened, about 4 minutes.

add spinach and cook until all the moisture has evaporated

transfer spinach mixture to food processor

add parsley, dill, feta, and egg yolk and blend leaving mixture with texture

fill each mushroom cap with about 2 tsp. spinach filling

arrange mushrooms on baking sheet sprayed with cooking spray or lined with parchment paper

bake 5 to 7 minutes

let cool slightly for 2 minutes and serve hot