Preheat oven to 375°F (190°C). Position rack in the center.

In a small bowl, mix the minced garlic, chopped rosemary, chopped thyme, salt, black pepper and olive oil until combined into a paste.

Pat the turkey breast dry with paper towels. Rub the herb mixture all over the surface, getting under skin where possible for extra flavor.

Place the turkey breast in a shallow roasting pan or dish. Pour the chicken broth into the pan around the meat (not over it) to catch drippings and keep the oven moist.

Roast uncovered about 1 hour for a medium-sized boneless breast. Begin checking internal temperature at 50–55 minutes. The turkey is done at 165°F (74°C) in the thickest part. If bone-in, allow extra time and check near the bone.

Remove the turkey from the oven and tent loosely with foil. Let it rest 10–15 minutes to let juices redistribute.

For the gravy: pour pan drippings into a skillet, skim excess fat if desired, and simmer.

To thicken, whisk 1 tablespoon cornstarch with 2 tablespoons cold water to make a slurry, then stir into simmering drippings until glossy and slightly thickened. Adjust seasoning and strain if you want a smooth finish.

Slice the turkey across the grain into even slices and serve warm with the gravy.