- Butter for dish
- 2 1/2 pounds (about 1 1/8 kg) zucchini
- 2 1/2 teaspoons kosher salt (I use Diamond brand, use 1 1/2 of other brands)
- 1/2 cup (90 grams) plain, uncooked white rice
- 1 medium onion, minced (about 1 cup)
- 5 tablespoons (75 ml) olive oil, divided
- 2 large cloves garlic, mashed or finely minced
- 2 tablespoons (15 grams) all-purpose flour (optional)
- 1/2 cup milk, as needed, although water or broth of your choice would work just fine [1/2 cup needed for streamlined directions, less for original]
- 2/3 cup (55 grams) grated Parmesan cheese, divided
- Salt and pepper
Heat oven to 325 degrees F. Oil or butter a 2-quart baking dish, or 2 smaller 1-quart dishes (as I did, with the intention of freezing one).
Prepare zucchini: Wash zucchini and trim ends. Halve lengthwise, and if seeds are particularly large, core them out. Coarsely grate and place in a large bowl.
Prepare remaining ingredients: In a large frying pan, cook the onions slowly in 3 tablespoons oil for 8 to 10 minutes until tender and translucent. Raise heat slightly and stir several minutes until very lightly browned. Stir in garlic and cook another minute. Add uncooked rice and sauté for another two minutes. Season generously with salt and pepper.
Assemble gratin: Transfer to bowl with zucchini and stir together with 1/2 cup liquid of your choice and all but 2 tablespoons cheese. Taste and adjust seasoning if needed. Transfer to prepared baking dish.
Bake gratin: Cover tightly with foil and bake for 50 to 60 minutes, until rice within is cooked but not mush. Increase oven temperature to 450 degrees. Remove foil, drizzle top with remaining olive oil (or dot with butter), sprinkle on remaining cheese and bake uncovered until browned and crisp on top, about another 10 to 15 minutes. For extra color, you can run it under the broiler for one minute at the end.