How do I make Leftover Mashed Potato Donuts?
Here's a recipe for Leftover Mashed Potato Donuts:

Ingredients:

• 3 1/4 cups all purpose flour, plus more for dusting
• 2 teaspoons baking powder
• 1/2 teaspoon baking soda
• 1/2 teaspoon kosher salt
• 1/2 teaspoon ground nutmeg
• 8 tablespoons unsalted butter, softened
• 1/2 cup granulated sugar
• 1/2 cup brown sugar
• 1 cup mashed potato
• 2 large eggs
• 1 teaspoon vanilla extract
• 1/2 cup buttermilk
• 2 qt canola oil, for frying

Coating

• 1 cup granulated sugar
• 2 teaspoons ground cinnamon

Instructions:

1. Sift the flour, baking powder, baking soda, salt, and nutmeg into a medium bowl.
2. In a large bowl, cream the butter with an electric hand mixer on medium-high speed until light and fluffy, 1–2 minutes. Add the granulated and brown sugars and the mashed potatoes and cream until combined. Add the eggs and vanilla and mix until combined.
3. Add half of the dry ingredients to the mashed potato mixture and mix on medium speed until mostly incorporated. Add the buttermilk, and mix until almost combined. Add the rest of the dry ingredients and use a spatula to finish mixing until just incorporated.
4. Turn the dough out onto a lightly floured surface. Knead for 1–2 minutes, adding up to 1/4 cup (30 g) more flour as needed until the dough is cohesive and no longer sticky.
5. Use a rolling pin to roll out the dough to 1/2 inch (1 1/2 cm) thick, flouring the dough as needed.
6. Use a 3-inch (7 cm) round cutter to cut out donuts. Use a 1-inch (2 1/2 cm) round cutter to cut out holes from the centers. Set the donuts and holes on a baking sheet. Re-roll the dough scraps and cut out more donuts. Refrigerate the donuts and holes until ready to fry.
7. Heat the canola oil in a large pot fitted with a deep fry thermometer over medium heat until it reaches 375°F (190°C). Set a wire rack over a baking sheet and place nearby.
8. In a medium bowl, mix together the sugar and cinnamon. Set near the wire rack.
9. Working in batches, fry the donuts and holes in the hot oil for about 2 minutes per side, until deep golden brown. The donut holes will take less time than the donuts. Transfer to the wire rack to cool for 1 minute, then carefully toss in the cinnamon sugar.
10. Eat warm, or let cool completely.

Enjoy your Leftover Mashed Potato Donuts!