Preheat your oven to 350°F and position the rack in the center. In a small bowl, whisk together flour, baking powder, and salt; set aside for later use in the batter.

Place 4 tablespoons of butter and ½ cup brown sugar in a 9-inch round cake pan. Heat on the stovetop over medium heat, stirring constantly, until the mixture bubbles gently—about 2–3 minutes. Remove from heat and arrange peach slices in a single layer, then sprinkle with cinnamon and drizzle with honey.

In a large mixing bowl, cream together ½ cup softened butter and ¾ cup sugar until light and fluffy, approximately 3–4 minutes with an electric mixer. This aerates the batter, creating a tender, springy crumb structure for your warm peach cake.

Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Alternate adding the flour mixture and sour cream in three batches, beginning and ending with flour; mix until just combined between additions.

Stir in 1 teaspoon vanilla extract, then carefully pour the batter over the caramelized peaches. Smooth the top with a spatula, being careful not to disturb the fruit arrangement beneath the cozy summer peach upside down cake recipe layers.

Bake for 38–42 minutes, until a toothpick inserted into the cake portion (not the fruit) comes out clean. The top should be golden brown and spring back when lightly touched.

Let cool in the pan for 10 minutes, then carefully run a thin knife around the edges. Place a serving plate over the pan and invert quickly and confidently; leave the pan on top for 1 minute before lifting away to reveal the beautiful caramelized peaches.