Canola Oil, enough for 2 inches of oil in a 6-quart pot (or Dutch oven)
Instructions
Cake Donuts
In a medium mixing bowl, add cake flour, baking powder, baking soda and salt. Whisk to combine and set aside.
In the bowl of a stand mixer fitted with the paddle attachment, add butter and sugar. Cream on medium-high speed until smooth, about 2 minutes. Turn mixer to low. Add blood orange and lemon zests. Add egg yolks one at a time, mixing fully after each addition. Add sour cream and vanilla, then mix on medium speed until smooth.
Turn off mixer and add flour mixture. Turn mixer to low and mix just until incorporated. Wrap dough in plastic wrap and chill for at least an hour before using.
Once dough is chilled, cut the donuts. Lightly flour a baking sheet and set aside. Using a rolling pin, roll the dough to about ½-inch thick on a lightly floured surface, and cut with a floured donut cutter. (Reflour the surface and cutter while cutting as needed to prevent sticking.) Gather the scraps, re-roll and continue cutting. Place the cut donuts and holes onto your prepared baking sheet, and place in the refrigerator to chill while you heat the oil for frying.
Line a baking sheet with paper towels and a wire baking rack, and set beside the stove. Add enough oil to your 6-quart pot (or Dutch oven) so you have 2–3 inches of oil to fry in. Attach a candy thermometer to the side of your pot, being sure it’s not touching the bottom. Turn the stove to medium, and allow the oil to heat slowly up to frying temp of 350°F. (See Recipe Notes for frying tips.)
Glaze
While the oil is warming, make the glaze. Sift powdered sugar and cardamom into a large mixing bowl. Add the blood orange juice and salt, then whisk until smooth.
Fry the Donuts
Dust any excess flour from the donuts and gently place them into the oil (about three donuts at a time). NOTE: do not overcrowd the frying pan, and remember: donuts will expand a bit while they fry. Allow to fry for about a minute and a half, then use your slotted strainer to gently flip the donuts to the other side. Donuts will be a a deep, golden brown when ready. Remove the donuts to your paper-towel lined plate, and allow to rest until cool to the touch, 2–3 minutes.
Dip the warm donuts into the prepared glaze, then set the donuts on the wire baking rack to allow glaze to set.