Start by cutting a circle out of each slice using a glass or dough cutter, then set aside.
In a large bowl, add the ground beef, the salt, a pinch of black pepper, the grated onion, the bell peppers cut into small cubes, the 3 circles of bread we just cut out and mix everything very well until combined.
Now, in another medium bowl, add the eggs, season them with the salt, a pinch of black pepper and mix until combined.
Grease a large skillet with the butter and add the bread slices with a hole in the center.
Fill each slice with the meat mixture we prepared.
Add 1 egg yolk on top of each one then spread these yolks covering the meat.
Next, add the egg mixture we prepared.
Take it to a preheated oven at 180° C (350° F) and bake for 20 minutes.
After this time has passed, add the grated cheddar cheese on top of everything.
Take it back to the oven and bake until the cheese has completely melted.
Serve.