In a pressure cooker, heat olive oil (with Instant Pot, press “Saute” and keep the default heat setting) then add the onion, garlic, jalapeno and chopped bell pepper. Cook until the vegetables are softened, then add the ground beef, spices and salt. Break up the beef into crumbles, and continue cooking until it's fully browned. If the beef renders an excess of fat, push it to one side of the pot and tip to drain some grease, skimming it out with a ladle. Stir in the salsa and corn. Arrange the halved bell peppers in a steamer basket, and generously stuff them with the beef mixture. To the remaining filling in the pressure cooker, stir in the quinoa and water, then place the basket of stuffed peppers on top.

Cover the pressure cooker with the lid, ensuring that the valve is in sealed position. Cook under high pressure for 1 minute (with Instant Pot, press ‘Manual’ mode, and adjust time to 1 minute).

When the cooking time is complete, immediately and carefully open the valve to release pressure. Open the lid and sprinkle 1 tablespoon of grated cheese over each pepper, then close the lid again for another minute or two to melt the cheese. Serve the quinoa and stuffed peppers together, topped with chopped cilantro if desired.