• Cook the pasta shells according to the package instructions for oven-ready pasta, or boil them for 1–2 minutes less than the recommended al dente cooking time. Drain and set aside.
• Heat the olive oil in a skillet over medium-low heat. Add the onion and bell pepper and cook for 3–5 minutes, or until the onions start to turn translucent.
• Sprinkle the taco seasoning over the onions and bell peppers, stirring to coat and toast the spices for about 30 seconds. Add the black beans, corn, cream cheese, and ¼ cup of salsa. Stir until the cream cheese has melted and everything is well combined.
• Spread a thin, even layer of salsa across the bottom of an 8 × 10-inch baking dish. Fill each pasta shell generously with the bean and corn mixture and arrange them in the baking dish, filling side up. Repeat until all the shells are filled and arranged in the dish. Pour the remaining salsa evenly over the shells, then sprinkle with the shredded cheese.
• Cover the baking dish with aluminum foil and bake in a preheated 350°F oven for 25 minutes. Remove the foil and bake for another 10 minutes, or until the cheese is melted, bubbly, and lightly golden.
• Remove from the oven and let the shells rest for 5 minutes before serving. Garnish with fresh cilantro and serve with sour cream if desired.

Make-Ahead Instructions

• Cover the assembled dish with aluminum foil and refrigerate until ready to bake. When ready to cook, place the covered dish in a preheated 350°F oven and bake for 35–40 minutes. Remove the foil and bake for an additional 5 minutes, or until the cheese is melted and bubbly.