Step 1

If the bell peppers don't sit upright on your cutting board, trim about 1/8 inch off the bottom to make level. Cut the top 1/2 inch off each pepper. Remove and discard the stem, then finely chop the remaining flesh from the trimmed top. Scoop out the seeds and as much of the membranes as you can. Set the hollowed-out bell peppers aside.

Step 2

Set a 6-quart Instant Pot® to high saute (see Cook's Note). Add the olive oil to the pot; once it's shimmering, add the chopped bell pepper, onion, garlic, 1/2 teaspoon salt and several grinds of black pepper. Cook, stirring occasionally, until vegetables are just tender, about 4 minutes. Add the ground beef, then cook, breaking up the meat with a wooden spoon into small pieces, until no longer pink, about 4 minutes more. Stir in the diced tomato, chicken broth, tomato paste, chili powder, thyme, 1 teaspoon salt and several grinds of black pepper. Cook, stirring occasionally, until the tomato starts to break down and the mixture becomes thick and saucy, 3 to 4 minutes. Stir in 1 cup of the Cheddar and the rice until cheese is melted and rice is combined. Taste and adjust the seasoning with salt and black pepper. Turn off the saute function, then spoon the filling into the reserved bell peppers. Wipe out the Instant Pot bowl.

Step 3

Set the rack into the bottom of the pot, then pour in 3/4 cup water. Add the stuffed bell peppers (they should fit snuggly).

Step 4

Follow the manufacturer's guide for locking the lid and preparing to cook. Set to pressure cook on high for 5 minutes. After the pressure-cook cycle is complete, follow the manufacturer's guide for quick release and wait until the quick-release cycle is complete (this should take about 1 minute). Being careful of any remaining steam, unlock and remove the lid, then top the stuffed peppers with the remaining 1/2 cup Cheddar, dividing evenly. Place the lid back on the pot and let stand until the residual steam melts the cheese, about 1 minute. Use tongs and/or a large spoon to transfer the stuffed peppers to a plate and sprinkle with the parsley.