Pasta Dough:
2 cups all-purpose flour, or as needed
2 large eggs
Filling:
1 cup ricotta cheese
½ cup shredded mozzarella cheese
¼ cup grated Parmesan cheese
Egg Wash:
1 cup water
1 large egg
Make the dough: Place flour into a large bowl and make a well in the center. Crack eggs into the well; gently beat eggs with a fork until blended, then use the fork to gradually draw flour in from the sides. Mix until all flour is incorporated.
Turn dough out onto a lightly floured surface; knead until smooth and elastic, 3 to 4 minutes. Cover with plastic wrap and let rest for at least 20 minutes.
Make the filling and egg wash: Mix ricotta, mozzarella, and Parmesan together in a bowl. Whisk water and egg together in another bowl.
Bring a large pot of salted water to a boil.
While the water is coming to a boil, prepare the ravioli: Lightly flour the work surface again. Roll dough into a thin sheet; cut with a heart-shaped cookie cutter. Brush the edges of each heart with egg wash. Spoon filling into the center of 1/2 of the hearts. Place remaining hearts, egg wash-side down, over filling; press edges together to seal.
Working in several batched, cook ravioli in boiling water until they float to the top, 1 to 2 minutes, then cook for 3 to 4 more minutes. Use a slotted spoon to transfer to a colander.
