1 Preheat oven to 350F (180C).2 Place the sliced apples in a 9x13 inch (22x33 cm) pan. Mix the brown sugar 1 Tbsp (15 mL) flour and ground cinnamon together, and sprinkle over apples.3 In a bowl combine the flour, oatmeal, brown sugar, baking soda and salt. Cut in the margarine until mixture is crumbly. Spread evenly over the apple mixture. Bake for about 45 minutes.