Step 1: Make the Cake Batter

Preheat your oven to 350°F (175°C). Grease and flour a 9-inch bundt pan.
In a large bowl, combine the flour, sugar, baking powder, baking soda, salt, and cinnamon.
In another bowl, whisk together the butter, eggs, vanilla extract, and sour cream until smooth.
Add the wet ingredients to the dry ingredients and stir until well combined. Fold in the chopped apples.
Pour the batter into the prepared bundt pan and smooth the top with a spatula.
Step 2: Bake the Cake

Bake for 50-55 minutes, or until a toothpick inserted into the center comes out clean.
Let the cake cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely.
Step 3: Make the Caramel Sauce

In a saucepan, melt the butter over medium heat. Stir in the brown sugar, heavy cream, and salt.
Bring the mixture to a gentle simmer, cooking for 5-7 minutes, or until it thickens.
Remove from heat and stir in the vanilla extract. Let the sauce cool slightly.
Step 4: Caramelized Apple Topping

In a separate pan, cook thin apple slices with butter and brown sugar for about 10 minutes, until the apples soften and caramelize.