Peel zucchini; remove seeds and slice as you would apples for pies (about 6 cuts). Put zucchini and lemon juice in saucepan; cover and cook over medium heat until tender, stirring occasionally (15 minutes). Add sugar, nutmeg and cinnamon. Blend well together. Remove from heat, pour into greased 13x9 pan. Mix all toppings in a bowl until crumbly. Sprinkle over zucchini. Bake at 350°F for 40 - 45 minutes until golden brown. Serve with ice cream.