Slow-Cooker Fajita Beef Barbacoa with Monterey Jack

This slow-cooker fajita beef barbacoa is the ultimate set-it-and-forget-it dinner. Cubes of beef chuck, rainbow bell peppers, red onions, and lime juice are topped with sour cream and Monterey Jack, then left to simmer low and slow until the beef is fork-tender and the sauce is creamy and rich.

Serve it with warm flour tortillas for a meal that feels like a fiesta but takes minutes to assemble.

When a craving for fajitas hits but the energy for standing over a hot skillet doesn't, this slow-cooker version delivers all the flavor with none of the fuss. The beef chuck cubes break down into shreds that soak up the tangy lime and mellow heat from the peppers, while the sour cream and Monterey Jack melt into a luxurious sauce that coats every bite.

It's a dump-and-forget meal that transforms simple ingredients into a hearty, satisfying dinner. The best part? The slow cooker does all the work while the day goes on.

Ingredients

Why this recipe works

Slow cooking is the key to turning tough, affordable beef chuck into melt-in-your-mouth shreds. The low, steady heat breaks down the collagen in the meat, rendering it tender and juicy.

Unlike high-heat cooking, which can toughen meat, the slow cooker allows the beef to relax and absorb the flavors of the lime, peppers, and onions. The result is a barbacoa-style filling that is both deeply savory and subtly bright.

The combination of sour cream and Monterey Jack creates a creamy, slightly tangy sauce that complements the beef without overwhelming it. As the cheese melts, it emulsifies with the sour cream and the juices from the meat, forming a silky sauce that clings to the shredded beef.

This technique is a classic slow-cooker trick: layering dairy on top and letting it meld slowly yields a sauce that tastes like it simmered for hours—because it did.

Notes and substitutions

Choose beef chuck cubes that are well-marbled; the fat renders during cooking and keeps the meat moist. If the cubes are large, cut them into 1-inch pieces for even cooking. Bell peppers in three colors add visual appeal and a mix of sweet and slightly bitter notes. Red onions soften into mild, sweet strands that pair beautifully with the lime juice.

A 7-quart slow cooker is ideal for this recipe, as it allows the ingredients to fit comfortably without overcrowding. If using a smaller slow cooker, reduce the beef to 2 pounds and adjust the vegetables accordingly. Full-fat sour cream is recommended for the best texture; low-fat versions can curdle. Monterey Jack melts smoothly, but pepper Jack can be swapped in for a spicier version.

• beef chuck cubes: Beef stew meat or round steak, cut into 1-inch cubes
• sour cream: Plain Greek yogurt (full-fat for best texture)
• Monterey Jack cheese: Pepper Jack cheese for a spicier kick
• flour tortillas: Corn tortillas (gluten-free option)

Equipment

• Slow cooker (7-quart or larger)
• Cutting board
• Chef's knife
• Measuring spoons
• Measuring cups
• Serving spoon