Combine sugar, cinnamon stick, and moscato in a small saucepan and bring to a boil, stirring occasionally. Continue to boil for about 10-12 minutes or until the mixture is reduced and coats the back of the spoon. Remember, it will thicken some as it cools. I like to err on the too thin side rather than the gummy/burnt side. Remove from heat and allow to cool. Discard cinnamon stick.

Mix together flour, oats, and brown sugar. Use your fingers or a pastry cutter to work the butter into the flour mixture until small, coarse crumbles form.

Prepare the plums by slicing them in half and removing the pits. Dig out a small hole in the center and if you'd like cut a very shallow X through the center. Be sure not to cut through the skin.

Place the halves on a parchment lined baking sheet or in individual ramekins. Fill each hole with about a Tablespoon of the wine sauce then cover with the crumble.

Bake at 350 for 20-25 minutes or until the crumble is browned and set. Serve warm with whipped cream, ice cream, or mascarpone cheese.