*The easiest way to remove the seeds is to cut the zucchini in half length wise then scoop out the seeds with a spoon. After all the seeds are removed, the zucchini should look like a large piece of celery.
Choose a LARGE zucchini only (preferably 12-24 inches long and very thick). Peel zucchini. Make sure all seeds are removed and slice the zucchini into thin slices.
In a large saucepan over medium heat add zucchini, lemon juice, white sugar, brown sugar, cinnamon and nutmeg. Cook for about 20 minutes or until zucchini is very tender.
Remove from heat and set aside.
Crust
Preheat oven to 375 degrees F. Prepare a 10 x 15 inch baking dish. (A 9×13 also works, that is what I used)
In a large bowl, combine flour, sugar, oats, baking powder and cinnamon.
Crumble chilled butter into flour mixture with hands (you can also use a pastry cutter) until mixture resembles coarse crumbs or pea sized butter bits.
Stir 1/2 cup of flour mixture into cooled zucchini mixture.
Press half of remaining butter mixture into bottom of prepared pan and bake for 10 minutes.
Spread zucchini mixture over top of crust and sprinkle remaining butter mixture over zucchini.
Bake for 35-45 minutes or until top is golden brown.