Mildly sweet and creamy, butternut squash is the perfect backdrop to the flavor of warm curry powder that shines through in these burgers. Chickpeas and oats make the patties hearty plus add plenty of fiber and protein to keep you satisfied.
Preheat oven to 400°F. Spread cubed squash in an even layer on a large parchment-lined rimmed baking sheet; drizzle with olive oil. Roast until tender, 25 minutes. Transfer to a shallow bowl, and mash with a fork.
Pulse oats in a food processor until finely ground, about 5 times. Add chickpeas, salt, garlic, and 1 teaspoon curry powder, and pulse until chickpeas are finely chopped, about 8 times. Transfer mixture to a medium bowl, and stir in mashed squash. Form squash mixture into 4 patties (about 3/4 cup per patty).
Heat coconut oil in a large nonstick skillet over medium-high. Cook patties until browned on each side, about 3 minutes per side. Transfer patties to a plate.
Stir together mayonnaise and remaining 1/4 teaspoon curry powder in a small bowl, then spread 1/2 tablespoon on bottom half of each bun. Top each with 1 cooked patty, 1/4 cup arugula, 1 tomato slice, and 1 onion slice. Cover with bun tops.