Place each spaghetti squash on a large cutting board, cut off the stem end with a chef’s knife, then stand the squash upright and carefully slice it in half from top to bottom.

Use a spoon to scoop out the seeds and stringy center from each half, making a clean cavity.

Line a baking sheet with parchment paper, then drizzle 2 tbsp olive oil over the cut sides of the squash with a measuring spoon.

Sprinkle 1 tsp kosher salt and ½ tsp black pepper on the cut sides, then rub the oil and seasoning around with your hand so the surfaces are evenly coated.

Place the squash halves cut side down on the baking sheet and put the sheet on the middle rack of a preheated 400°F oven using oven mitts.

Roast for 35 minutes until the squash shells give slightly when pressed and the flesh feels tender when tested with the tip of a knife.

While the squash roasts, add the black beans, corn, diced tomatoes or salsa, and chopped red onion to a large mixing bowl.

Sprinkle 1 tsp chili powder, 1 tsp cumin, ½ tsp smoked paprika, ½ tsp salt, and ¼ tsp pepper over the mixture with measuring spoons.

Add 1 cup shredded cheese and 1 tbsp lime juice to the bowl and stir everything together with a wooden spoon until the filling looks evenly mixed and coated with spices.

When the squash is done, remove the baking sheet from the oven with oven mitts and let the halves cool for 5 minutes so they are easier to handle.

Turn the squash halves cut side up on the baking sheet with a spoon, then use a fork to scrape the inside of each half, pulling the flesh into long spaghetti-like strands while keeping the shells intact.

Gently pull most of the strands into the center of each shell, leaving a thin layer against the skin to keep the bowl sturdy.

Transfer the loose strands from all halves into the large mixing bowl with the black bean mixture and stir with the wooden spoon until the squash strands are evenly combined with the filling.

Spoon the squash and black bean mixture back into the four squash shells on the baking sheet, mounding the filling so each shell looks full but stable.

Sprinkle the remaining ½ cup shredded cheese over the tops of the stuffed squash.

Return the baking sheet to the oven on the middle rack and bake at 400°F for 10 minutes until the cheese melts and the filling is heated through.

Take the baking sheet out with oven mitts and let the bowls rest for 3 minutes, then sprinkle chopped cilantro over the tops and add avocado slices or extra salsa if you like.

Serve each Southwest spaghetti squash bowl directly in its shell on a plate as a main dish.