Caramelized Onion and Brie Melts in Mushroom Cups

1. Caramelize Onions

To begin, melt the salted butter in a medium saucepan over medium-low heat. Once the butter has melted, add the thinly sliced onion and cook until it becomes translucent. This should take a few minutes. Sprinkle in the salt, reduce the heat to low, and continue to cook the onions for about 15 minutes, stirring frequently. This slow cooking process will bring out the natural sweetness of the onions, turning them a beautiful golden brown.

2. Prepare Mushrooms

While the onions are caramelizing, preheat your oven to 400°F and line a rimmed baking sheet with parchment paper or aluminum foil. Prepare the cremini mushrooms by removing their stems and placing the caps in a bowl. Drizzle the mushrooms with the avocado oil, and season them generously with salt and black pepper. Toss them gently to ensure they're evenly coated.

3. Fill and Bake Mushrooms

Arrange the seasoned mushroom caps cavity side up on the prepared baking sheet. Once your onions are perfectly caramelized, divide them among the mushroom caps, filling each cavity. Then, cover each filled mushroom cap with a slice of Brie cheese.

4. Bake and Serve

Bake the mushroom caps in the preheated oven for 12 to 15 minutes, or until the mushrooms have softened and the Brie has melted into a gooey delight. Keep an eye on them, as cooking times can vary slightly. Once baked, garnish the mushroom cups with chopped fresh herbs if desired, and serve them immediately. Enjoy the perfect blend of sweet caramelized onions and creamy Brie in every bite.