Loaded Cheeseburger Casserole with Caramelized Onions

By AislePrompt Editorial · Published 2026-04-06 · Updated 2026-04-06

A hearty casserole packed with ground beef, caramelized onions, and creamy cheese sauce for a satisfying keto meal. This American-inspired keto recipe (low-carb), ready in about 55 minutes, pairs ground beef, yellow onion, olive oil for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 550 calories and feeds 4, so it slots cleanly into a low-carb week and pairs well with cauliflower rice or roasted green vegetables. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Ingredients

• 1 lb ground beef
• 1 medium yellow onion
• 2 tbsp olive oil
• 1/2 cup keto tomato sauce
• 1/4 cup cheddar cheese
• 1/4 cup mozzarella cheese
• 1/4 cup sour cream
• 1/4 tsp garlic powder
• 1/4 tsp onion powder
• 1/4 tsp salt
• 1/8 tsp black pepper

The 9x13 baking dish we’d bake this in → Best Bakeware for 2026: Top Picks + Buying Guide

Instructions

1. Step 1: Heat 1 tbsp olive oil in a skillet over medium-high heat. Add 1 lb ground beef and cook, breaking it up, until browned (6-7 minutes). Drain excess fat.
2. Step 2: Add 1 cup finely diced yellow onion to the skillet. Cook for 8 minutes until golden and caramelized, stirring occasionally.
3. Step 3: Stir in 1/2 cup keto tomato sauce, 1/4 tsp garlic powder, 1/4 tsp onion powder, 1/4 tsp salt, and 1/8 tsp black pepper. Simmer for 5 minutes until thickened.
4. Step 4: Transfer mixture to a 9x13-inch baking dish. Top with 1/4 cup cheddar, 1/4 cup mozzarella, and 1/4 cup sour cream.
5. Step 5: Bake at 375°F for 20 minutes until bubbly and cheese is melted.