Preheat oven to 350. Lightly oil a 9×9 baking pan or casserole dish. Spread fruit evenly in the pan and add apple juice. In a food processor, pulse 1/2 the oats until they are a flour-like consistency. Combine maple sugar, oats and oat flour, walnuts, cardamom, cinnamon, cloves and sea salt. Cut the butter into small pieces and work it into the oat flour mixture until it resembles medium-sized crumbs. Lay the oat crumbs on top of fruit. Cook, uncovered, 35-45 minutes or until mixture is bubbling and oat flour is browned.