Steakhouse Mushroom Burgers with Creamed Spinach Sauce

We love burgers, so I'm always on the lookout for fun new recipes and ideas.  This burger is inspired by a steakhouse menu.  It is ground sirloin, mixed with sauteed mushrooms and spices, and topped with a creamy, spinach sauce.  Served open-faced on a piece of grilled Texas toast, this is definitely a fork-and-knife burger.

We all really liked these burgers, and Caroline especially loved dipping hers in the spinach sauce.  This is definitely a little bit heavier fare than we normally eat, but paired with a green salad or some grilled vegetables, it balances out nicely.  And since it is a little fancier than a typical burger, this is a great option to serve company.

Steakhouse Mushroom Burgers
adapted from Cuisine Tonight:  Grilling
makes 4 burgers

• 8 oz mushrooms, sliced
• 3 Tbs olive oil, divided
• 2 cloves garlic, minced
• 1 lb ground sirloin
• 1 Tbs low-sodium soy sauce
• 2 tsp minced fresh thyme
• 2 tsp minced fresh parsley
• 1 Tbs Dijon mustard
• 1/2 tsp kosher salt
• 1/2 tsp black pepper
•   4 slices buttered Texas Toast
• shredded Parmesan

Creamed Spinach Sauce
makes 2 cups

• 2 Tbs unsalted butter
• 1/4 cup minced onion
• 2 Tbs all-purpose flour
• 1/2 cup half-and-half, plus more as needed
• 1/2 cup low-sodium chicken broth
• kosher salt and black pepper
• pinch cayenne
• pinch nutmeg
• 4 cups chopped fresh spinach
• 1 Tbs grated Parmesan
• squeeze of fresh lemon juice

Preheat the grill to medium-high.

In a medium saute pan, saute the mushrooms in 1 tablespoon of olive oil over medium-high heat.  Cook until the mushrooms begin to brown, 3-4 minutes.  Stir in garlic and cook until fragrant, about 1 minute.  Season with salt and pepper and remove from heat.

In a large bowl, combine the sirloin with 1 tablespoon oil, soy sauce, salt, pepper, mustard, herbs, and mushroom mixture.  Gently mix to combine using a fork or your hands.  Divide the mixture into 4 equal portions, shaping each portion into a patty.

Scrape the grate clean and brush with the remaining tablespoon of oil.  Grill the burgers until cooked through, 3-4 minutes per side.  Remove the burgers from the grill and cover to keep warm.  Grill the bread 1-2 minutes per side, until lightly browned.

To make the spinach sauce, melt the butter in a medium saucepan over medium-low heat. Add the onion and cook until translucent, 3-4 minutes.  Stir the flour into the onions and cook 1 minute.

Whisk in the half-and-half, broth, salt, cayenne, and nutmeg.  Bring sauce to a simmer, then reduce heat and simmer for 2 minutes, until it begins to thicken.

Add the spinach, stirring until wilted.  Mix in the Parmesan and lemon juice, and add more half-and-half if the sauce has thickened too much.  Season to taste with salt and pepper.

Top each slice of bread with a burger, spinach sauce, and garnish with Parmesan.  Serve immediately.