Peel the potatoes, rinse them under cold water, and dry thoroughly. Using a coarse vegetable grater, grate the potatoes into a large mixing bowl.

Wash, dry, and grate the zucchini, placing it in the same bowl as the potatoes.

Add the finely chopped onion and pressed garlic into the bowl.

Stir in the cornstarch, adding salt and pepper to taste. Combine everything well to ensure even seasoning.

Add the grated cheese and the fresh egg into the mixture. Give it a sturdy stir until fully integrated.

Drizzle olive oil in a large skillet and heat it over medium-high heat.

Once hot, scoop about 1 large tablespoon of the mixture into the skillet. Flatten it gently with the back of the spoon to form a fritter. Repeat until the pan is filled without overcrowding.

Reduce the heat to medium, and carefully cook each fritter for about 5 to 7 minutes on each side, or until they are golden brown.

If necessary, repeat the frying process until all the mixture is cooked. Generally, you should yield around 6 to 8 fritters with this amount of mixture.