In a large sauce pot, add brown sugar and water. Bring to a simmer over medium-high heat until sugar has melted and formed a thin, brown syrup, about 5 minutes.
Add Dei Fratelli Tomato Sauce, nutmeg, ginger, and onion. Cook for an additional 10 minutes over medium heat, stirring frequently. Glaze should look sticky and evenly coat the back of a spoon.
Once oven is preheated, put ham on a wire baking rack over a baking sheet. Place pan in the oven for 3 hours (cooking times may vary depending on size - follow package instructions). Baste ham every 30 minutes with a brush until cooking is finished.
For a little boost in sweetness, add sugar or honey to taste.