Slice the sausages into 2 cm pieces and place them at the bottom of the slow cooker.
In a deep skillet over medium heat, brown the onions in the butter for about 3 minutes.
Add the ketchup, brown sugar, vinegar, mustard, Worcestershire sauce and hot sauce. Simmer for 20 minutes, stirring occasionally.
Pour the sauce with the onions into the slow cooker and cook at low intensity for about 5h. Check the doneness of the sausages and serve over white rice with steamed broccoli.