Mushrooms and 1 onion cut and fry. Separately from the mushrooms sauté the ground beef and 1 onion. Sprinkle with salt and pepper. Connect together.
Zucchini grate on a grater and sprinkle with salt, so that the excess liquid came out. Press. I have frozen zucchini out of it while defrosting and the moisture. Add eggs, flour, a little pepper, a little salt. Beat with a mixer.
Heat oven to 200*. Form (large and rectangular) cover with baking paper, lightly lubricate with vegetable oil. Pour and level the squash puree. Bake for 20 minutes.
On the baked base spread the minced meat with mushrooms, grated cheese on top.
Turn into a roll and send in the oven for 10 minutes at 180*.