Start by cutting a thin slice of the zucchinis and scoop out the center of each one of them.
Into a skillet, add a drizzle of oil and the onion chopped into dices, stir until slightly golden brown.
Add the potatoes chopped into dices and let it all cook for 4 minutes.
Add the red pepper chopped into dices and keep stirring.
Add the chopped mushrooms and let it all cook for 2 minutes.
After this indicated time, season with the minced garlic clove, the salt and the black pepper, stir well again.
Once you’ve done that, get some of this filling and fill the zucchini we scooped out.
Repeat this process with all the zucchinis.
Then add two egg yolks to each zucchini.
And fill the remaining gaps with grated mozzarella cheese.
Transfer the zucchinis to a baking sheet lined with parchment paper.
Take to a preheated oven at 180°C (356°F) and let them bake for 40 minutes.
Serve.