Apple Cider Donut Cake

Preheat the oven to 350ºF and set an oven rack in the middle position. Butter or coat an 8-inch square metal baking pan with nonstick spray. Line the pan with an 8x16-inch piece of parchment paper, leaving a 2-inch overhang on two sides. Create seams in the corners and along the edges to keep it in place.

In a small skillet, bring the apple cider to a boil over medium heat. Gently boil until the cider is reduced to ½ cup, about 10 to 15 minutes. Let it cool for about 10 minutes. Measure out ⅓ cup and leave the remaining reduced cider in the skillet.

In a large bowl, whisk the sugar and eggs until pale and foamy, about 1 minute. Whisk in the sour cream, followed by the butter, nutmeg, vanilla, salt, and the ⅓ cup of reduced cider. Whisk until evenly combined. Add the flour, baking powder, and baking soda and whisk until smooth.

Pour the batter into the prepared pan and bake until the cake is puffed and golden and a skewer inserted into the center comes out clean, about 30 to 35 minutes. Set the pan on a rack to cool for about 15 minutes, then use the parchment paper to lift the cake out of the pan and set it on the rack to cool.

To make the glaze: To the skillet with the remaining reduced cider, add the butter, sugar, and salt. Bring to a boil over medium heat and gently boil until very thick, about 30 to 60 seconds. Drizzle the warm cake evenly with the glaze. Let the glaze set for a few minutes while you make the cinnamon-sugar topping.

In a small bowl, mix the cinnamon and sugar until evenly combined. Sprinkle a generous layer of the mixture evenly over the glazed cake, reserving a bit to add a fresh dusting before serving, if desired. Cut the cake into squares and serve.