Peel and grate the zucchini and onion. Either a box grater or a food processor will work fine.
(Optionally, toast the fennel seeds in a skillet over medium heat for a few minutes to bring our the flavor.)
Mix the turkey, grated onion and zucchini, and all seasonings thoroughly.
Heat a tablespoon or two of fat in a skillet over medium heat until sizzling hot. (It is worth the time to get it very hot, as your mixture will stick much less if you do!) Shape your turkey mixture into patties and brown them for a few minutes with a cover over the pan (to speed the cooking).
Turn when the bottoms are brown and the tops are no longer pink. When cooked through, remove to a plate.
Either continue cooking all your turkey patties now, or package the rest to store in the refrigerator or freezer until you need it. (I usually put some uncooked mixture in the refrigerator for the next couple of days and freeze what is left, often doubling the recipe.)