Step 1

Preheat oven to 375 degrees F. Gently clean mushrooms by wiping them with damp paper towels.

Step 2

Remove stems from mushrooms; place mushroom caps on baking sheet. Finely chop the stems.

Step 3

In a large skillet, melt butter over medium-high heat. Add chopped mushrooms, onion, and garlic, and saute 4 to 5 minutes, or until tender. Add spinach and sausage; mix until well combined. Remove from heat and add bread crumbs; mix well.

Step 4

Evenly divide spinach mixture on top of each mushroom cap and mound with a spoon.

Step 5

Bake 15 to 20 minutes, or until heated through. Serve immediately.