1/4 cup ( 1/2 stick) butter, room temperature
1/4 cup vegetable or canola oil
1/2 cup packed brown sugar
1/3 cup granulated sugar
1 1/2 teaspoons baking powder
1/4 teaspoon baking soda
1/2 teaspoon salt
1 teaspoon vanilla extract
Zest of 1 lemon
2 1/2 cups all-purpose flour
1 cup buttermilk
2 tablespoons lemon juice
1 cup powdered sugar
Heat the oven to 425 degrees. Coat 2 doughnut pans with baking spray; you can use pans designed for either large or small doughnuts. A mini doughnut pan will bake more quickly.
In a medium bowl, use an electric mixer to beat together the butter, oil, brown sugar, granulated sugar, baking powder, baking soda, salt, vanilla and lemon zest. Beat in the eggs, one at a time, scraping the bowl between additions.
Stir in half the flour followed by half the buttermilk, then the remaining flour and finally the remaining buttermilk. Spoon the batter into the prepared pans, filling the doughnut wells to about 1/4 inch from the top. If using a mini doughnut pan, you will need to bake in multiple batches. Bake for 10 to 12 minutes, or until golden and cooked through. Allow to cool in the pan for 10 minutes before turning out onto a rack.
To make the glaze, stir together the lemon juice and powdered sugar. Dip the tops of the doughnuts in the glaze and allow to set or enjoy immediately.
Per serving (assumes large doughnuts): 280 calories; 90 calories from fat (32 percent of total calories); 10 g fat (3.5 g saturated; 0 g trans fats); 40 mg cholesterol; 45 g carbohydrate; 1 g fiber; 24 g sugar; 5 g protein; and 210 mg sodium.