01 -
Position rack in upper third of oven and preheat broiler to high.
02 -
Heat olive oil in a large broiler-safe skillet over medium heat. Add onion and bell pepper and cook, stirring, until softened, about 5 minutes.
03 -
Add ground beef and cauliflower to the skillet. Cook, stirring and breaking up the beef, until no longer pink, 5 to 7 minutes.
04 -
Stir in garlic, chili powder, cumin, oregano, salt, and chipotle. Cook until fragrant, about 1 minute.
05 -
Add diced tomatoes with juices. Bring to a simmer and cook, stirring occasionally, until liquid is reduced and cauliflower is tender, about 3 minutes. Remove from heat.
06 -
Sprinkle cheese over the mixture and top with sliced jalapeños. Broil until cheese is melted and browned in spots, 2 to 3 minutes.