Place the beef chunks, sliced onion, garlic, and ginger in the slow cooker.
Add the Thai red curry paste, coconut milk, fish sauce, and brown sugar. Stir to coat the beef evenly.
Cover and cook on low for 7 hours.
Stir in the sliced bell peppers and continue cooking for 1 more hour until the peppers are tender but still hold their shape.
Turn off the heat and stir in the lime juice.
Spoon the curry over cooked jasmine rice and top with chopped cilantro before serving.