Portobello Mushrooms Stuffed with French Onion Soup Recipe - unsalted butter

Method

• Heat the oven to 400 degrees F and arrange a rack in the top third.
• Melt 2 tablespoons of the butter in a large frying pan over medium heat.
• Add the onions and thyme, season generously with salt and pepper, and cook, stirring rarely and adjusting the heat as needed, until golden brown, about 35 minutes.
• Meanwhile, roast the mushrooms and toast the bread.
• Set a wire rack over a baking sheet.
• Clean the mushrooms and remove the stems (no need to scrape the gills).
• Brush both sides of the mushrooms with all of the oil and season generously with salt and pepper.
• Arrange the portobellos cap-side down on the rack.
• Roast the mushrooms for 8 minutes.
• Flip and roast until they just give way when pierced with a knife but still hold their shape, about 8 minutes more.
• Set the baking sheet aside to let the excess liquid drain from the mushrooms.
• Place the remaining tablespoon of butter in a medium microwave-safe bowl and heat until melted (alternatively, melt it in a small saucepan over low heat).
• Cut the bread into 1/2-inch cubes, add them to the bowl, season with salt and pepper, and toss to combine.
• Transfer the cubes to a second baking sheet and spread them in an even layer (reserve the bowlno need to wash it).
• Bake until toasted and golden brown, stirring halfway through, about 10 minutes total.
• Transfer the toasted bread to the reserved bowl and set it aside (reserve the baking sheetno need to wash it).
• Turn the oven to broil.
• When the onions are ready, add the sherry and cook, stirring occasionally, until completely evaporated, about 1 to 2 minutes.
• Remove from the heat, taste, and season with additional salt and pepper as needed.
• Place the mushrooms cap-side down on the reserved baking sheet.
• Divide the onions over the mushrooms.
• Divide the toasted bread over the onions and use your hands to gently press the bread into an even layer.
• Sprinkle the mushrooms evenly with the cheese.
• Broil until heated through and the cheese is melted and starting to brown in spots, about 2 minutes.
• Serve immediately.