Meanwhile, wash cranberries; remove blemished berries. In 2-quart saucepan, mix 1/2 cup granulated sugar and cornstarch. Stir in water. Heat to boiling over medium-high heat, stirring occasionally. Stir in cranberries; return to boiling. Simmer uncovered 5 to 8 minutes, stirring occasionally, until cranberries pop. Stir in marmalade. Cover; refrigerate until serving time.