Preheat the oven to 350°F and lightly grease a doughnut pan.
Combine the ricotta cheese, granulated sugar, olive oil, 2 tablespoons lemon juice, zest, egg, egg yolk, and vanilla in a mixing bowl.
Whisk until well combined.
Combine the flour, baking powder, salt, and nutmeg in a small mixing bowl and mix.
Fold the flour into the ricotta mixture, mixing just until combined.
Fill the spaces in the doughnut about ⅔ full, smoothing the top and keeping the center free of batter.
Bake for 15-17 minutes, until a toothpick comes out clean.
Let cool a few minutes in the pan before turning out onto a cooling rack.
Repeat with the remaining batter if needed.
Paint the tops of the warm doughnuts lightly with the remaining lemon juice and press into the chunky sugar.
That’s-a nice-a doughnut.
