Preheat oven to 375°. Spray a 2 1/2 quart casserole dish with non stick cooking spray; set aside.
Combine flour, sugar, cinnamon, and salt in a mixing bowl. Cut in butter until crumbly.
Press about 1/3 of the mixture into the prepared pan. Bake for 12 minutes.
Bring cubed zucchini and lemon juice to a boil in a large pan. Reduce heat and simmer for 8-10 minutes, or till crisp tender. Stir in sugar, cinnamon, and nutmeg.
Cover and simmer 5 minutes. (Mixture will be thin.)
Spoon zucchini mixture over the baked crust; sprinkle with reserved crumb mixture.
Bake for an additional 40-45 minutes, or till golden brown.
Serve warm with a scoop of vanilla ice cream.
Notes
-This works best with the large zucchini that grow to the size of a leg when you aren't watching.