Tender, cakey donuts infused with reduced apple cider, cinnamon, and brown sugar, then finished with a crackly cinnamon-sugar coating. Cozy fall flavors in an easy, baked treat.
Pour apple cider into a small saucepan over medium heat and simmer until reduced to 1/2 cup, about 20 minutes; let cool for 10 minutes.
In a large bowl, whisk together flour, brown sugar, granulated sugar, salt, ground cinnamon, and baking powder.
In a medium bowl, whisk the cooled reduced cider, melted butter, vanilla extract, milk, and egg until combined.
Add the wet ingredients to the dry ingredients and mix just until incorporated; do not overmix.
Preheat oven to 350°F (175°C). Grease donut pan(s). Spoon or pipe batter into wells, filling about 2/3 full.
Bake 12–13 minutes, until golden and a toothpick comes out clean or the donuts spring back when gently pressed.
Cool in the pan for a few minutes, then transfer donuts to a wire rack.
For the coating, melt 6 tablespoons butter in a shallow bowl; in a separate shallow bowl, mix granulated sugar and ground cinnamon.
Dip warm donuts in melted butter, then roll in the cinnamon-sugar mixture to coat. Serve warm.