1. Place walnuts, sugar, brown sugar and cinnamon in a blender or food processor (a), process until nuts are finely chopped.
2. Core the apples and peel two-thirds of the skin off from the top. Brush the bare apple with butter (b), then press the walnut sugar mixture onto the apple (c).
3. Stand apples in a baking dish (d) and cook in moderate oven for 45 minutes. Serve with whipped cream.