To make the gnocchi, in a bowl, mix together the ricotta and egg. Add 2 cups flour, the parmesan, and 1 teaspoon salt. Stir until just combined. If the dough feels wet, add a 1/4 cup flour at a time until the dough can be formed into a ball. The dough should be sticky, but not so wet that it sticks to your hands.
Generously flour the counter and scrape the dough out onto it. Cut the dough into four pieces. Working with one piece of dough at a time, roll the dough into a rope about 1-inch thick and cut into bite size pieces. Repeat this process, placing the gnocchi on a floured baking sheet. At this point, the gnocchi can be kept covered in the fridge for up to 1 day. Simply boil just before you're ready to eat. Or boil right away.
Bring a large pot of salted water to a boil. Boil the gnocchi until they float to the top and are cooked through, about 3-4 minutes. Drain.
Meanwhile, heat the olive oil in a large skillet over high heat. When the oil shimmers, add the mushrooms and season with salt and pepper. Cook undisturbed for 5 minutes or until golden. Reduce the heat to medium. Add the butter, garlic, thyme, and sage. Cook, stirring occasionally until the butter is browning and the sage is crisp, about 4-5 minutes.
Drop the gnocchi into the butter sauce, gently tossing to combine. Remove from the heat.