Step 1

Place racks in lower and upper thirds of oven; preheat to 375°. Toss onions, 3 Tbsp. oil, and a large pinch of salt on a large rimmed baking sheet. Bake on lower rack, tossing every 5 minutes, until onions are browned and frizzled, 30–40 minutes.

Step 2

Meanwhile, toss both squashes, honey, Aleppo-style pepper, and 2 Tbsp. oil on another large rimmed baking sheet. Season with salt. Arrange in an even layer and bake on upper rack until tender, 25–30 minutes.

Step 3

When onions are ready, remove from oven and increase oven temperature to 450°. Continue to bake squash until browned, about 10 minutes longer.

Step 4

Meanwhile, combine yogurt, garlic, ½ bunch dill, olive brine, half of the frizzled onions, and remaining 5 Tbsp. oil in a blender and purée until smooth. Add olives and pulse until finely chopped. Season to taste with salt.

Step 5

Divide rice among bowls. Pour ½ cup sauce over each. Arrange roasted squash over rice. Top with remaining frizzled onions and garnish with dill.