Preheat oven to 275°F. Heat a Dutch oven over medium-high heat. Sprinkle beef pieces with salt. Add oil to the pan and when it is hot, brown the beef pieces thoroughly, three pieces at a time, setting pieces aside on a plate as you go.
When all the beef is browned, lower heat to medium, and add onion, garlic, ginger, lime zest, and curry paste and saute for 2-3 minutes. Stir in coconut milk, brown sugar, and fish sauce. Settle beef pieces into the pan (and any accumulated juices from the plate) and cover tightly. Bring to a simmer, then transfer pot to the oven. (Alternately, transfer the coconut milk mixture to a crock pot. Settle the beef pieces into the crock pot. Add the bell pepper. Cover and cook on low setting for 8-10 hours. Season with lime juice and adjust seasoning per instructions below.)
Bake for 2-3 hours, or until beef is falling apart (or “fork”) tender. Remove beef pieces to a cutting board. Set pan over medium heat and when it simmers, stir in bell pepper and simmer uncovered for a few minutes until pepper is tender. Stir in lime juice and taste sauce for seasoning – add more fish sauce for saltiness, more maple syrup for sweetness, more lime for sourness. Stir in scallions and basil. Pull beef into bite-sized pieces and add back to the pan. Serve with rice or cauliflower rice.