Heat the oven to 450°F.
Trim the ends off the squash and slice crosswise into four (1 1/2 to 2-inch) rings. Use a large spoon to scoop out the seeds. Arrange on a baking sheet.
Brush both sides of each ring lightly with oil and season all over with 3/4 teaspoon of the salt and several grinds black pepper. Roast, flipping halfway through, until the squash flakes easily with a fork but is still al dente, 20 to 25 minutes. (Don’t overcook!)
Meanwhile, in a large bowl, combine the beans, cottage cheese, cilantro, chili powder, cumin, 1/2 cup of the cheddar, a few dashes hot sauce, remaining 1/2 teaspoon salt and several grinds black pepper.
Heat the oven to broil. Flip over the end pieces of squash so they’re bowl-shaped. Scrape a few strands of the squash into the center of each ring to fill in the hole and create a nest for the filling (you may not need to do this for the end pieces). Divide the cottage cheese mixture between each ring, followed by salsa (2 tablespoons per ring). Top with the remaining cheese.
Broil until the cheese is melted and browned in spots, 2 to 4 minutes (watch it carefully). Top with your desired toppings: more cilantro, avocado, pepitas, a dollop of yogurt or sour cream, a squeeze of lime, a few dashes hot sauce, etc.
