Wash the swiss chard and pinch off the leaves at the top of the stem. Discard the stems.
Chop the garlic cloves.
Heat 2 tablespoons of olive oil in a skillet. Add the chopped garlic.
Add in the chopped chard in the skillet.
Reduce heat to medium and cook until pieces are tender.
Introduce into the skillet the ricotta, the Parmesan cheese, salt, black pepper, nutmeg, and crushed red pepper.
Stir and adjust the seasoning to taste.
Scoop out the centers of the mushroom using a small spoon.
Place a little bit of the chard filling into the cavity of each mushroom.
Place each filled mushroom onto a greased pan. Bake in oven for 20 minutes or until mushrooms become tender.