In a large bowl, combine ricotta cheese, eggs, parmesan, a pinch of salt and several turns of ground black pepper. Add ½ cup flour and stir. Continue to add flour until the dough comes together.
Using a spoon, scoop a small bit into the dough ( about 1 teaspoon) and drop it into the boiling water. If the gnocchi hold it’s shape, then you have added just the right amount of flour. Stir in a bit more flour and repeat the testing process above till your gnocchi holds together.
Line a baking sheet with foil or parchment paper. Scoop tablespoon sized gnocchi onto the baking sheet. Set aside while preparing the sauce.
To make the sauce:
Warm butter and olive oil in a large skillet over medium high heat. Cook just until the butter begins to brown, about 2 minutes. Add mushrooms and sliced onion and cook, stirring occasionally, until golden brown, about 10 minutes.
Add stock, parsley and stirring to combine. Simmer until liquid is slightly reduced ( 6-8 minutes). Stir in heavy cream, then season to taste with kosher salt and freshly ground black pepper. Reduce heat to low to keep sauce warm while gnocchi are cooking.
Bring a large pot of water to a boil and salt well. Working in small batches ( about 6-8 gnocchi at a time depending on size), drop gnocchi into the boiling, salted water. When the gnocchi rise to the surface, scoop out a slotted spoon and add to the skillet with the mushroom sauce. Repeat until all gnocchi are cooked.
Return heat to medium, add chopped parsley. Finish with a healthy dusting of freshly grated Parmesan cheese.