Preheat your oven to 375°F (190°C).

In a large skillet, add diced bacon and cook until crispy and golden, about 5–7 minutes. Remove bacon and let drain.

In the same skillet, sauté chopped onion and minced garlic in bacon grease until onion is translucent, about 2–3 minutes.

Add ground beef to the skillet and cook until browned, about 5–6 minutes. Drain any excess grease.

Stir the crispy bacon back into the skillet with the beef mixture and cool for about 5 minutes.

In a mixing bowl, whisk together eggs, heavy cream, yellow mustard, Worcestershire sauce, salt, and pepper until smooth.

Spread the beef and bacon mixture evenly in a greased 8x8-inch baking dish.

Sprinkle shredded cheddar cheese over the beef mixture.

Pour the custard mixture over the beef and cheese layers.

Bake in the preheated oven for 25–30 minutes until top is set and golden brown.

Cool for about 5–10 minutes before serving, and optionally garnish with green onions and tomatoes.