Chop the onion and sauté in a small amount of olive or vegetable oil until browned. Combine the sugar, mustard, and place in the crock-pot.
Cut the kielbasa into one inch thick slices and add to the crock-pot.
Stir to coat. Cover and cook on low heat 2-1/2 to 3 hours, stirring
occasionally. 6 servings.
Variations: Use a spicy barbecue sauce in your favorite brand instead of the sugar mixture. This is not a "set in stone" recipe! You can use smoked cocktail sausages as well, and more or less sauce, depending on what you prefer!