On medium-high heat, melt butter and saute your onions until tender.
Next, add and saute zucchini.
Add all the spices and mix well.
Shred cheese and set aside.
Crack and mix eggs in a separate large bowl.
Pour in the egg mixture, cheese, and then pour in your zucchini mixture. Combine well.
Prepare crust (printable recipe linked below) and add the mustard to the bottom of the pie crust and spread it around.
In your crust-lined pie plate add the zucchini mixture, then prepare your second pie pan the same way you did the first, and then pour the other half of the mixture into it.
You can add strips of foil to cover the edge of crust, to protect the crust from burning. However, I have not found that necessary for this particular pie. It will really just depend on how your oven bakes.
Bake for 25-30 minutes or until fully cooked. (If you are making a larger pie like we do, you will want to bake it for 35 to 40 minutes, or until fully cooked.
We like to dip our pie in mustard but, some of the kids prefer ketchup.