Reduce Apple Cider (Vital Flavor Secret): In a small saucepan over medium heat, simmer 1 1/2 cups apple cider for 15 to 20 minutes until reduced down to exactly 1/2 cup. This concentrates the apple flavor tenfold! Cool for 10 minutes.

Prep Oven & Donut Pan: Preheat oven to 350°F (175°C). Generously grease a 12-cavity donut pan with non-stick baking spray or melted butter.

Whisk Dry Ingredients: In a large bowl, whisk together flour, baking soda, baking powder, salt, cinnamon, nutmeg, and cardamom.

Whisk Wet Batter: In a medium bowl, whisk together the cooled reduced apple cider, melted butter, egg, brown sugar, granulated sugar, buttermilk, and vanilla until smooth and blended.

Combine & Pipe: Pour wet ingredients into dry and fold gently with a silicone spatula just until incorporated. Transfer batter to a gallon zip-top or piping bag, snip the corner, and pipe evenly into prepared donut cavities (about 3/4 full).

Bake to Golden: Bake at 350°F for 10 to 12 minutes, or until the donuts spring back immediately when gently pressed with a fingertip. Cool in pan for 5 minutes, then turn out onto a wire rack.

Butter & Cinnamon Sugar Roll: Melt 6 tbsp butter in a shallow bowl. In another bowl, mix 1 cup sugar and 1 1/2 tbsp cinnamon. Dip each warm donut into melted butter, then toss generously in cinnamon sugar until thickly coated!