Preheat the oven to 400°F (200°C). Slice the acorn squash in half, scoop out the seeds, drizzle with olive oil, and season with salt and pepper. Place cut sides down on a parchment-lined baking sheet and bake for 25-30 minutes until tender.

Rinse quinoa under cold water. In a medium saucepan, combine quinoa with 2 cups of water and a pinch of salt. Bring to a boil, then reduce to a simmer and cover, cooking for about 15 minutes until fluffy.

In a large skillet, heat olive oil over medium heat. Add chopped onion and minced garlic, stirring until fragrant, about 3-4 minutes. Add diced bell peppers and corn, sautéing for 5-7 minutes until vegetables are tender.

Add the cooked quinoa to the skillet with sautéed vegetables. Stir in the drained black beans and season with cumin, paprika, salt, and pepper. Mix well and heat through for 2-3 minutes.

Remove the roasted squash from the oven and flip the halves so cut sides are facing up. Spoon the quinoa filling into each half, pressing down gently. Return to the oven and bake for an additional 10 minutes.

Once out of the oven, let cool briefly and top with sliced avocado and fresh cilantro before serving. Enjoy warm!