1. Prep the Mushrooms: Start by cleaning and drying your baby bella mushrooms. Remove the stems and set them aside. Place the mushrooms top side down in an oven-safe pan. Preheat your oven to 350°F (175°C).

2. Caramelize the Onions: Peel and roughly chop your onions until you have about 3 cups. In a 12” skillet, melt ½ cup of butter over low heat. Add the chopped onions and cook slowly, stirring occasionally, until they turn soft, golden, and caramelized. This process takes about 30–45 minutes, so be patient—it's worth it!

3. Add the Garlic: Once the onions are beautifully caramelized, stir in the minced garlic and cook for 2 minutes until fragrant. Remove the skillet from heat and let it cool for about 5 minutes.

4. Make the Filling: After the onion mixture has cooled slightly, stir in ½ cup of breadcrumbs. If you see butter pooling at the bottom of the pan, add the extra ¼ cup of breadcrumbs a little at a time until the butter is mostly absorbed but the mixture is still moist and buttery. Next, gently mix in 3 ounces of blue cheese.

5. Stuff the Mushrooms: Spoon the filling generously into each mushroom, mounding it high. Top each stuffed mushroom with a small chunk of the remaining blue cheese for an extra hit of flavor.

6. Bake: Bake the mushrooms at 350°F for 12–15 minutes, until the cheese is melted and the filling is golden brown.

7. Serve: Garnish with chopped parsley if desired and serve immediately. These are best enjoyed warm and gooey!