Gluten Free Chocolate Sheet Cake

Name: Gluten Free Chocolate Sheet Cake
Prep time: 10 min
Cook time: 30 min
Total time: 40 min
Cuisine: American
Ingredients: 1/2 cup butter, unsalted, room temperature; 3/4 cup sugar; 1/2 cup applesauce, unsweetened; 1 tbsp vanilla extract; 1/4 cup pure maple syrup; 1/2 cup melted semi sweet chocolate chips; 1 1/4 cup unsweetened almond milk; 1 cup superfine almond flour; 1 1/2 cup gluten free all purpose flour; 1/3 cup cocoa powder; 1 tsp baking soda; 2 tsp baking powder; 1/2 tsp salt; Christmas nonpariels, optional; 2 sticks unsalted butter, room temperature; 1 1/2 cups powdered sugar; 1 tsp vanilla extract; 1/2 cup melted and cooled, dark or semi sweet chocolate; pinch of salt