Preheat oven to 375 degrees F (190 degrees C). Grease an 8x8-inch baking pan with coconut oil.
Combine honey, maple syrup, vanilla extract, cinnamon, allspice, cardamom, cloves, ginger, and nutmeg in a shallow bowl. Coat apple slices in half the honey mixture and arrange in the prepared baking pan.
Combine remaining honey mixture, oats, and walnuts in a bowl; sprinkle mixture over apples.
Bake in the preheated oven until golden, 15 to 20 minutes.
You don't have to use dark honey specifically, but it really goes well with the maple syrup flavor. Also, the spices can come off a little strong for some people, so please adjust them to your preference.