Pour 2 cups of apple cider and a cinnamon stick into a small saucepan over medium heat. Simmer for 15 to 20 minutes until reduced down to exactly 1/2 cup of rich, fragrant amber syrup. Discard cinnamon stick and let cool completely (reserve 3 tbsp for glaze).

Preheat oven to 350°F (175°C). Generously grease and flour a 9x5-inch loaf pan or 10-cup Bundt pan.

In a large stand mixer fitted with paddle attachment, beat softened butter, granulated sugar, and brown sugar on medium-high speed for 4 to 5 minutes until pale, fluffy, and voluminous.

Add eggs one at a time, beating thoroughly after each addition. Beat in pure vanilla extract.

In a separate bowl, whisk together flour, baking powder, sea salt, cinnamon, grated nutmeg, and allspice.

With mixer on low speed, alternate adding the dry flour mixture (in 3 additions) and the cooled reduced cider combined with sour cream (in 2 additions), beginning and ending with dry ingredients. Mix just until combined without over-working the batter.

Spread the thick, aromatic batter evenly into the prepared pan. Bake at 350°F for 50 to 55 minutes, or until a wooden skewer inserted into the center emerges clean with a few moist crumbs.

Let cake cool in the pan for 15 minutes, then invert onto a wire cooling rack set over a baking sheet.

In a small bowl, whisk together the reserved 3 tablespoons of reduced cider, sifted powdered sugar, melted butter, and ground cinnamon until glossy and pourable.

Drizzle warm glaze generously over the cake, allowing it to soak into the warm crust and drip down the sides. Let set for 10 minutes before slicing warm into generous bakery slices!