Winter Crisp

FOR FILLING
1/2 C sugar
3 Tbsp all-purpose flour
1 tsp lemon peel, grated
3/4 tsp lemon juice
5 C apples, unpeeled, sliced
1 C cranberries

FOR TOPPING
2/3 C rolled oats
1/3 C brown sugar, packed
1/4 C whole wheat flour
2 tsp ground cinnamon
1 Tbsp soft margarine, melted