Preheat oven to 350° and grease a 9″ springform pan with cooking spray. In a large bowl toss together apples, lemon juice, and 2 tablespoons brown sugar.
In a large bowl whisk together flour, baking powder, salt, cinnamon, and nutmeg.
In another large bowl using hand mixer (or in the bowl of a stand mixer), beat together butter, granulated sugar, and remaining 1/2 cup brown sugar until light and fluffy. Add eggs one at a time beating well after each addition. Add vanilla and mix until combined.
Add half of the dry ingredients to the wet ingredients, beating until just combined. Pour in protein shake and mix until fully incorporated. Add remaining dry ingredients and stir until just combined.
Pour batter into prepared pan and arrange apples on top in a spiral, overlapping layers slightly. Sprinkle with coarse sugar.
Bake until a toothpick inserted into the middle comes out clean, about 1 hour. Let cool 10 minutes before removing sides of springform pan.