In a large saucepan over medium heat, cook and stir zucchini and lemon juice until zucchini is tender, 15-20 minutes. Stir in 1 cup sugar, 1 tsp cinnamon and nutmeg and cook one minute more. Remove from heat and set aside.
Preheat oven to 375° F. Grease a 10x15 inch baking dish.
In a large bowl, combine flour and 2 cups sugar. Cut in butter with pastry blender or two knives until mixture resembles coarse crumbs.
Stir 1/2 cup of butter mixture into zucchini mixture. Press half of remaining butter mixture into bottom of prepared pan. Spread zucchini mixture over top of crust and sprinkle remaining butter mixture over zucchini.
Sprinkle with 1 tsp cinnamon. Bake 35-45 minutes or until top is golden. Serve warm or cold.