Preparation:
Preheat your oven to 180°C (350°F). Grease a large rectangular or round cake pan (or line it with parchment paper for easy release).
Prepare the Apples:
Peel, core, and dice the apples into small cubes. In a small bowl, toss the diced apples with a sprinkle of cinnamon and set aside to allow the flavors to meld.
Make the Browned Butter:
In a small saucepan, melt the butter over medium heat. Continue cooking it until it turns a golden brown color and gives off a nutty aroma, being careful not to burn it. Remove from heat and let it cool slightly.
Mix Dry Ingredients:
In a mixing bowl, combine the ground hazelnuts, flour, sugar, ground cinnamon, and a pinch of salt. Whisk together until evenly combined.
Combine Wet Ingredients:
In another bowl, mix the diced apples with the slightly cooled brown butter. Once combined, add the dry ingredients to this mixture and stir until well blended.
Bake:
