Heat oven to 450°F (230°C).
- Combine ricotta, garlic and egg yolk in a medium bowl. Stir in parmesan, flour, salt, pepper and nutmeg just until combined.
- Dust a rimmed baking sheet with some additional flour and using a tablespoon or small cookie scoop, scoop gnudi into approximately two tablespoon (30 gram) portions. Roll into balls and place on prepared sheet. Toss or roll gnudi on baking sheet to coat in flour; set aside.
- Place tomatoes on a rimmed baking sheet and toss with olive oil. Season with salt and pepper. Place in oven and roast until starting to brown, about five to seven minutes.
- Place butter in a large stainless steel pan set over medium heat. Allow the butter to melt, foam and then bubble, stirring occasionally until butter is beginning to brown.
- As soon as the butter is golden, add in the black pepper and allow it to toast for about 30 seconds. Add in lemon zest and remove from heat.
- Boil a large pot of water. Add gnudi ten at a time and cook until they float, about three to four minutes. Using a slotted spoon, transfer gnudi into brown butter mixture.
- When gnudi have all been cooked, reserve 1/4 cup (60 milliliters) cooking water.
- Turn butter pan back on to medium heat. Add tomatoes and gnudi cooking water to the pan and simmer for five minutes. Stir in lemon juice and season with salt. Sprinkle with basil and Parmesan-Reggiano.