Beef Stroganoff Burgers

Ingredients:

• 5 portobello mushrooms (110-140 g each)
• 2 tbsp + 2 tsp olive oil
• 1 small onion, diced
• 1 medium clove garlic, minced
• 1 teaspoon flour
• 0.5 cups lightly salted beef broth
• 1/4 cup low-fat sour cream
• 3 tbsp chopped fresh parsley
• 1 tbsp Dijon mustard
• 2 tsp Worcestershire sauce
• 450 g ground beef, 5% fat
• 4 hamburger buns
• Lettuce leaves for assembly

Preparation:

1. Preheat oven to 220°C (425°F). Trim the stems from 4 mushrooms and set them aside. Place 4 caps, stems removed, gill-side up in a large baking dish, leaving at least 1/2 inch (1 cm) between them. Drizzle with 2 tablespoons of olive oil. Season with salt and pepper. Bake until a knife inserted into the center of the mushroom inserts easily, 20-25 minutes. Remove from the dish and keep warm.
2. Wipe and roughly chop the mushroom stems and the remaining whole mushroom. Heat the remaining 2 teaspoons olive oil in a medium nonstick skillet over medium heat. Add the onion and a pinch of salt and cook, stirring, until softened and translucent, about 4 minutes. Add the sliced ​​mushrooms, garlic, and pepper; cook until the mushrooms are tender, about 4 minutes.
3. Sprinkle the flour over the onions and mushrooms and stir until all the flour is absorbed. Add the beef broth. Bring to a boil and simmer, stirring, until the sauce thickens, about 5 minutes. Remove from heat and stir in the sour cream, parsley, mustard, and Worcestershire sauce. Keep warm while you fry the patties.
4. Form the ground beef into four 12-cm (5-inch) patties. Season generously with salt and pepper. Heat a nonstick grill pan over medium heat. Once hot, spray the pan generously with cooking spray. Add the patties and cook until golden brown, about 2 minutes. Flip the patties and cook for another 1.5 minutes, or until medium-rare.
5. Place the bottom halves of the buns on serving plates. Top with a lettuce leaf and a fried mushroom, slices down, then add a patty and a spoonful of sour cream and mushroom sauce. Top with the tops of the buns and serve.