Step 1: Preheat your oven to 325°F (160°C). Grease and flour a 10-12 cup Bundt pan thoroughly, ensuring all crevices are coated. Set aside.
Step 2: In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
Step 3: In a large bowl with an electric mixer, cream together the softened butter and granulated sugar on medium speed until light and fluffy, about 3-5 minutes.
Step 4: Add the eggs one at a time, beating well after each addition until fully incorporated. Scrape down the sides of the bowl as needed.
Step 5: Beat in the vanilla extract.
Step 6: With the mixer on low speed, alternately add the flour mixture and sour cream to the butter mixture, beginning and ending with the flour mixture. Mix until just combined, being careful not to overmix.
Step 7: Prepare the cinnamon swirl: In a small bowl, combine the brown sugar, cinnamon, and melted butter. Mix until a thick paste forms.
Step 8: Pour half of the pound cake batter into the prepared Bundt pan. Spoon dollops of the cinnamon swirl mixture evenly over the batter. Gently swirl with a knife or skewer, being careful not to overmix into the batter.
Step 9: Spoon the remaining pound cake batter over the cinnamon swirl layer, spreading it evenly to cover the swirl. You may need to gently tap the pan on the counter a few times to settle the batter.
Step 10: Bake for 60-70 minutes, or until a wooden skewer inserted into the center of the cake comes out clean. If the top starts to brown too quickly, you can tent it loosely with foil.
Step 11: Remove the cake from the oven and let it cool in the Bundt pan for 15-20 minutes before inverting it onto a wire rack to cool completely. This is crucial before glazing.
Step 12: While the cake cools, prepare the glaze: In a medium bowl, beat the softened cream cheese and softened butter with an electric mixer until smooth and creamy.
Step 13: Gradually add the sifted powdered sugar, caramel sauce, and vanilla extract, beating until smooth. Add milk or cream one tablespoon at a time until the glaze reaches your desired drizzling consistency.
Step 14: Once the cake is completely cool, drizzle the caramel cream cheese glaze generously over the top. For extra flair, drizzle with additional caramel sauce if desired. Slice and serve!