Place breasts on lightly sprayed, foil lined baking sheet and bake in oven.
Meanwhile, in a small saucepan, melt butter over medium heat. Add jam, vinegar, rosemary, red pepper flakes and salt; stir to combine. Simmer for 3 to 5 minutes for flavors to meld. Set aside and keep warm.
Bake frozen breasts, about 25 minutes, until internal temperature reaches 165° F.
Remove cooked breasts from oven and brush both sides with glaze. Return glazed breasts to baking sheet and place under the broiler for 1-2 minutes to caramelize.
Serve chicken breasts with additional glaze on the side or spooned on top. Yields 1 chicken breast per serving.