Heat the olive oil in a saucepan and sauté the ground beef with the onion for 5 minutes, seasoning with salt and pepper.
In the meantime, grate the zucchini. Add to the saucepan with the pepper and cook for 5 more minutes.
Pour in the crushed tomatoes and the stock, season with dried mint, and cook for about 20 minutes to combine the flavors, adding a bit of water if needed.