Mix minced meat with egg, breadcrumbs, chopped onion and spices. Fill the prepared peppers.
To prepare the rice, fry the chopped onion in the lard. Add the rinsed rice and sauté. Stir in the chopped mushrooms and carrots.
Pour in broth (I recommend broth or at least stock) and season with salt and pepper as needed. Add the peppers, cover the baking dish and place in a preheated oven at 200 degrees Celsius.
Bake until the rice is tender, about 30 minutes, (use your oven experience). Then uncover the baking dish and bake for a while to colour.