Curried Sweet Chili Ribs

Name: Curried Sweet Chili Ribs
Ingredients: 3 Tbsp. Diamond Crystal or 1 Tbsp. plus 2¼ tsp. Morton kosher salt; 2 Tbsp. Madras curry powder; 1 Tbsp. garlic powder; 1 tsp. crushed red pepper flakes; 1 tsp. finely grated lime zest; 1 tsp. freshly cracked pepper; 1 tsp. ground ginger; 1 tsp. ground turmeric; 2 racks St. Louis–style pork spareribs (3½–4 lb. total); 2 small onions, thinly sliced; 1 Tbsp. unsalted butter or refined coconut oil; 1 Tbsp. Madras curry powder; 5 garlic cloves, finely chopped; 2 Tbsp. finely chopped onion; 1 Tbsp. tomato paste; 1 cup sweet chili sauce (such as Mae Ploy); ¼ cup ketchup; 1 Tbsp. hot sauce; Vegetable oil (optional)