Celebrate peak season zukes by stuffing them with a hearty mixture of sausage, rice, and basil, and then baking them with zippy tomato sauce and lots of Parmesan cheese.
Allergen Note: Contains milk.
Preheat the oven to 375ºF. Line a sheet pan with parchment or foil.
Cut the zucchini in half lengthwise. Scrape out the seeds and flesh with a small spoon, leaving behind a shell about ⅓ inch thick. Place cut-side up on the prepared sheet pan, drizzle with 1 tablespoon olive oil, and season with salt and pepper. Dice half of the onion, reserving the rest for another use (you should have about 1 cup). Pick the basil, toss the stems, and slice the leaves. Squeeze the pouch of rice to separate the grains.
In a large skillet over medium heat, warm 1 tablespoon olive oil. Add the sausage and onions, and cook, breaking up the sausage with a spoon, until the sausage is cooked through and the onions are softened, about 5 minutes. Remove from the heat and stir in half of the basil, half of the Parmesan (about ¼ cup), 1 cup of the rice, and ¼ cup of the arrabbiata sauce. Season to taste with salt and pepper.
Divide the filling between the zucchini shells, heaping and packing it in. Spoon ½ cup of the sauce over the filling, then sprinkle with the remaining Parmesan. Bake until the zucchini is crisp-tender, 30 minutes.
Transfer the stuffed zucchini to plates, sprinkle with the remaining basil, and serve warm, with the remaining arrabiata sauce on the side, if desired.
The sausage may arrive frozen for freshness. Store it in the refrigerator to defrost before cooking. If you need to defrost it same day, place the sealed package in a bowl of cold water, and leave the tap running in a thin stream for about 30 minutes.