Mix Spice Rub: Stir together smoked paprika, ground cumin, salt, and black pepper in a small bowl until combined.

Prep Roast: Pat the beef chuck roast dry, rub with olive oil, then press the spice rub and minced jalapeños all over the surface.

Sear Roast: Heat olive oil in a large skillet over medium-high heat, then sear each side of the roast for 2 to 3 minutes.

Layer Ingredients: Transfer the seared roast to the slow cooker, scatter sliced onions, minced garlic, and halved jalapeños around it, then pour beef broth to cover the bottom.

Cook Low and Slow: Cover and cook on low for 8 hours or high for 5 hours until the beef is tender.

Rest and Slice: Transfer the roast to a cutting board, tent with foil, let rest for 10 minutes, then slice thinly.

Garnish and Serve: Arrange sliced roast on a platter, spoon cooking juices over, sprinkle with fresh cilantro, and serve with lime wedges.