Ingredients
1 envelope (1/4 ounce) instant yeast
1/4 cup granulated sugar
3/4 teaspoon salt
1/4 teaspoon ground nutmeg
3 3/4 cups all-purpose flour, plus more for dusting
1 cup buttermilk, room temperature
2 large eggs, plus 1 large egg yolk
4 tablespoons unsalted butter, softened, plus 4 tablespoons melted
Vegetable oil, for bowl
1 cup seedless strawberry jam
Confectioners' sugar, for rolling
Preparation
Whisk yeast, granulated sugar, salt, nutmeg, and 3 cups flour in a medium bowl; set aside. Mix buttermilk, eggs, and yolk on high speed in the bowl of a mixer fitted with the dough hook until combined. Mix in flour mixture on low speed until combined. Mix in softened butter, 1 tablespoon at a time (dough should form a ball).
Gradually add remaining 3/4 cup flour, mixing until dough is tacky but not sticky. Transfer to a lightly oiled bowl; cover with plastic wrap. Let dough rise in a warm, draft-free spot until doubled in bulk, about 1 hour 20 minutes.
Fit a pastry bag with a #230 filler tip. Stir jam until smooth; transfer to bag. Twist a rubber band around open end of bag to prevent jam from leaking; set bag aside.
Preheat oven to 375 degrees. Roll out dough 3/4 inch thick on a lightly floured work surface. Cut out rounds using a 1-inch cutter; transfer to a baking sheet. Let rise 25 minutes. Generously brush with melted butter. Bake until pale golden, about 10 minutes. Transfer to a wire rack; let cool slightly.
Insert tip of filled pastry bag into the side of each donut hole, and pipe jam to fill. The morning of the sale, roll in confectioners’ sugar; package in cellophane bags.
