Bake the cake:

Preheat the oven to 350°F. Spray an 8-inch round cake pan with coconut oil spray and sprinkle the sides with gluten free flour. Tap out any excess flour then line the bottom of the pan with parchment paper.

Place 2 tablespoons butter into the prepared pan, then place the pan in the oven until the butter is melted. Sprinkle brown sugar in an even layer over the melted butter then arrange the apple slices in a ring around the outside edge of the pan with the slices slightly overlapping each other.

In a large mixing bowl, beat the granulated sugar and the remaining 1/2 cup butter with a mixer at medium speed until fluffy, about 3-4 minutes, stopping to scrape the sides of the bowl as necessary. Add eggs, one at a time, beating well after each addition. Beat in the vanilla and the applesauce. Set aside.

In a separate bowl whisk together the remaining 1 1/4 cups gluten free all purpose flour, almond flour, baking powder, salt, cinnamon, nutmeg, and gingersnap seasoning (or ground ginger).

With the mixer on low speed, gradually add the flour mixture to the butter mixture alternately with the Premier Protein Vanilla Protein Shake or milk, beginning and ending with the flour mixture, beating until just combined after each addition. Pour the batter over the apple slices, smoothing the top with an offset spatula. gently tap the pan on the counter to release any air bubbles from the batter.

Bake for 35-40 minutes or until a wooden pick inserted in the center of the cake comes out clean. Run a knife around the edges of the cake to loosen then invert the cake onto a serving platter and gently remove the pan.

Make the caramel sauce:

In a small saucepan, heat the sugar, water, and salt over high heat, gently swirling the pan to combine.  Cook until golden brown, 5-7 minutes. Remove from the heat and carefully stir in the warm cream and butter. Drizzle the desired amount of caramel over the prepared cake.

If you have any leftover caramel, transfer to a heatproof bowl, and let cool. Refrigerate in an airtight container for up to 2 days. When ready to use, heat the caramel in the microwave in 15 second intervals until pourable.