Step 1: Prepare the Burger Patties: In a large bowl, gently mix ground beef with garlic powder, onion powder, 1 teaspoon salt, and 1/2 teaspoon black pepper. Avoid overmixing. Form into four equally sized patties, making a slight indentation in the center of each to prevent bulging.
Step 2: Cook the Patties: Heat a large skillet or grill to medium-high heat. Cook patties for 4-5 minutes per side for medium-rare, or until desired doneness is reached. Set aside to rest.
Step 3: Make the Beer Cheese Sauce: In a medium saucepan, melt butter over medium heat. Whisk in flour and cook for 1 minute to form a roux. Gradually whisk in milk until smooth, then add the beer. Bring to a simmer, stirring constantly.
Step 4: Finish the Sauce: Reduce heat to low. Add shredded cheddar cheese and Dijon mustard. Stir continuously until the cheese is completely melted and the sauce is smooth and creamy. Season with salt and pepper to taste. Keep warm.
Step 5: Toast the Buns: While the sauce is warming, lightly toast the pretzel buns on the grill or in a toaster until golden brown.
Step 6: Assemble the Burgers: Place a beef patty on the bottom half of each pretzel bun. Drizzle generously with beer cheese sauce. Add optional toppings like caramelized onions or crispy bacon. Top with the other half of the pretzel bun and serve immediately.