In a large bowl, thoroughly mix 1 portion of cold leftover risotto with 1 egg and 1 tablespoon of Parmesan cheese, ensuring the ingredients are well combined.
2 cups leftover risotto, 1 fresh eggs, 2 tablespoon freshly grated Parmesan
Over medium heat, melt the butter and the olive oil in a large nonstick skillet or frying pan, waiting until the butter foams without letting it brown.
1 tablespoon butter, 1 tablespoon olive oil
Carefully pour the risotto mixture into the center of the skillet, using a spatula to spread it evenly across the pan, forming a single, large cake.
Allow the risotto cake to cook undisturbed for 2-3 minutes, or until the bottom forms a golden brown crust, indicating it's crisped up nicely.
To flip the cake, place a large plate or a lid over the skillet, then carefully turn the skillet upside down, transferring the cake onto the plate.
Then, gently slide the cake back into the skillet to cook the other side.
Cook for an additional 1-2 minutes on medium heat until the second side is also golden brown and crispy.
Once cooked, transfer the large risotto cake onto a cutting board or a serving plate.
Cut the risotto cake into slices, similar to how you would serve a frittata or a pie, and serve immediately.