Blanche the onions: Using a sharp paring knife, trim off the very bottom of the stem ends of the onions and score a light "X" cut into the bottom. Bring a pot of water to a boil; add onions and cook for 1 1/2 minutes. Drain onions well and run under cold water until the onions are cool enough to handle. Peel onions with your fingers and discard skins.

Heat an oven proof skillet to medium on the stove top and add butter. Once butter has melted, add onions and sugar; stir gently so that all of the onions are covered with butter and sugar. Cook for 10 minutes or until the onions begin to brown.

Place pan in oven and cook for another 20 minutes, until the sauce thickens and the onions become tender. Remove from oven, season with salt, garnish with parsley and serve immediately.