• First, preheat your oven to 350°F.
• Generously grease two donut pans with nonstick cooking spray to ensure easy release.
• In a medium mixing bowl, whisk together the flour, sugars, baking powder, salt, and cinnamon until well combined—this forms the flavorful base for your cinnamon-infused donuts.
• Next, grab a spoon—a wooden one works especially well—and gently push the dry ingredients up against the sides of the bowl to create a spacious well in the center.
• Pour the eggs, oil, milk, and vanilla extract right into that well.Then, whisk everything together vigorously until the wet and dry ingredients are fully combined into a smooth, luscious batter.
• Now, for that signature king cake cinnamon swirl: In a small bowl, stir together the brown sugar and ground cinnamon until evenly combined. This fragrant mixture will add a warm, spiced ribbon of flavor throughout your donuts.
• Transfer the batter to a piping bag (or a large zip-top bag with one corner snipped off if you don’t have a piping bag).
• Pipe a small, even layer of batter into the bottom of each greased donut cup, filling them only about one-third of the way up.
• Now, generously sprinkle the brown sugar-cinnamon mixture evenly over the batter in each donut cup. This creates that irresistible, swirled ribbon of warm spice that makes king cake so iconic.
• Next, carefully pipe or spoon the remaining batter over the cinnamon-sugar layer in each donut cup, filling them about three-quarters full (or just below the top) to allow room for rising.
• Once all the cups are filled, place the pans in your preheated 350°F oven.
• Bake for 20 to 25 minutes, until the donuts are golden and spring back lightly when gently pressed with a finger.
• Remove the pans from the oven and let the donuts cool in the pans for 5 minutes. Then, gently turn them out onto a wire rack to cool completely.

While the donuts are cooling on the wire rack, prepare the luscious glaze:

• In a medium bowl, whisk together the powdered sugar, vanilla extract, and milk until completely smooth and pourable. This sweet, vanilla-scented icing will be the perfect canvas for those iconic Mardi Gras colors.
• Once the donuts are completely cool, it’s time for the grand finale! Dip the top of each donut into the smooth vanilla glaze, letting the excess drip off for a moment, then place them back on the wire rack to set. This glossy icing will give them that classic king cake shine and make the colorful sprinkles pop.
• While the glaze is still tacky (but before it fully hardens), generously sprinkle the iconic Mardi Gras colors—purple, green, and gold—over the top of each donut. This festive touch brings the true spirit of king cake to life!
• Let the glazed and sprinkled donuts sit on the wire rack until the icing sets completely. Then, serve and enjoy