The Yankees-Red Sox rivalry will take on a different, er, flavor with a cupcake competition this week involving former Bombers center fielder Bernie Williams and former Boston catcher Jason Varitek.

Georgetown Cupcake owner Sophie LaMontagne, star of The Learning Channel’s DC Cupcakes program, will team with Williams against her sister, Katharine Kallinis, and Varitek, to see which team can sell the most cupcakes over a six-day period through Sunday, July 22.

Williams and LaMontagne are offering the New York Pinstripe Pretzel, a Valrhona chocolate cake baked with butterscotch chips and crushed pretzels, topped with a butterscotch-infused buttercream frosting. Varitek’s and Kallinis’ entry is the Green Monstah cupcake, a green version of Georgetown Cupcake’s signature red velvet cupcake topped with vanilla cream cheese frosting.

The Boston-vs.-New York/Sister-vs.-Sister completion will begin Tuesday with Bernie’s arrival at Georgetown Cupcake’s Soho store at 111 Mercer Street between Spring and Prince Streets. Sophie chose to donate all proceeds of her special New York cupcake sales to Bernie’s charity, Hillside Food Outreach, which delivers groceries to needy families in Westchester and Putnam counties.

Varitek will join Kallinis Thursday at Boston’s Faneuil Hall to boost sales to support his charity, Pitching for Kids. The non-profit youth organization is dedicated to improving the lives of children across New England.

This is one case where the rivalry will have no losers.