Cranberry Walnut Upside Down Cake

Preheat the oven to 350 degrees F.

Melt the butter for the topping in a 10-inch cast iron skillet over medium heat. Add the brown sugar and cook, stirring constantly, until the sugar dissolves. Evenly sprinkle the sugar mixture with the cranberries and walnuts. Remove the pan from the heat and set aside.

Combine the flour, baking powder, baking soda, and salt in a bowl and whisk to combine.

In a large mixing bowl, beat the butter and sugar with an electric mixer on medium speed until light and fluffy. With the mixer running, add the eggs one at a time, beating well after each addition. Add the vanilla and mix for 1 minute.

Place the buttermilk in a bowl or large measuring cup and mix it with a whisk for 30 seconds.

With the mixer on low speed, alternately add the flour mixture and buttermilk in batches. Mix until combined, scraping down the sides of the bowl as needed.

Return the cast iron skillet to the stove and heat over medium-high heat. Cook, without stirring, until the sugar mixture starts to bubble.

Gently spoon the cake batter evenly over the topping, spreading it lightly so all the topping is covered with the batter.

Place the skillet in the oven and bake at 350 degrees F for 25-30 minutes or until a toothpick inserted in the center comes out clean.

Remove the cake from the oven and let cool on a wire rack for 15 minutes. Run a thin knife around the edge of the skillet to loosen the cake. Carefully invert the cake onto a serving platter (the skillet will be hot).

Let the cake cool completely before serving or storing in an airtight container.