Preheat the oven to 350°F (175°C). Thoroughly grease and flour a 10 to 12-cup (2.4 to 2.8 liter) Bundt pan, making sure every crevice is coated well. Cake goop also works well for this recipe.
Whisk together the flour, baking powder, baking soda, salt, cinnamon, and nutmeg in a medium bowl.
3 cups (360 g) all-purpose flour, 2 tsps (8 g) baking powder, ½ tsp (3 g) baking soda, 1 tsp (6 g) fine sea salt, 1 tsp (3 g) ground cinnamon, ½ tsp (1 g) ground nutmeg
In a large mixing bowl, beat the butter, brown sugar, and granulated sugar until light and fluffy, about 3 to 4 minutes. Add the eggs one at a time, mixing well after each addition. Mix in the vanilla extract.
1 cup (226 g) unsalted butter, 1½ cups (310 g) packed light brown sugar, ½ cup (100 g) granulated sugar, 4 large eggs, 1 tbsp (15 ml) vanilla extract
Add half of the flour mixture, followed by the sour cream, then the remaining flour mixture. Mix just until combined.
¾ cup (180 g) full-fat sour cream
Toss the peaches with the flour, then gently fold them into the batter. Coating the peaches with flour helps distribute them more evenly throughout the cake.
2 cups (300 g) peeled and diced fresh peaches, 2 tbsps (16 g) all-purpose flour
Transfer the batter to the prepared Bundt pan and smooth the top.
Bake for 50 to 60 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
Let the cake cool in the pan for 10 minutes before carefully inverting it onto a cooling rack. For a caramel topping that stays mostly on the surface of the cake, allow the cake to cool completely before drizzling. For a topping that soaks into the cake, drizzle while the cake is still warm.
To make the bourbon caramel, combine the brown sugar and butter in a small saucepan over medium heat. Stir frequently until the butter is melted and the mixture is smooth and gently bubbling around the edges. Slowly whisk in the heavy cream and continue whisking until smooth. Remove from the heat and stir in the bourbon, vanilla extract, and salt. Let the caramel cool for 5 to 10 minutes before drizzling. The caramel will thicken slightly as it cools.
1 cup (200 g) packed light brown sugar, 6 tbsps (85 g) unsalted butter, ½ cup (120 ml) heavy cream, 1 tbsp (15 ml) bourbon, 1 tsp (5 ml) vanilla extract
Drizzle the bourbon caramel over the cake before serving.