Heat a large drizzle of olive oil in a non stick skillet over medium high heat. Pat chicken dry with paper towel, then season all over with salt and pepper.
Add to pan and cook until no longer pink in center 4-5 minutes per side. Remove from pan and set aside to rest.
To pan, add shallot, whole thyme sprigs and drizzle of olive oil over medium heat. Cook, tossing, until shallot is soft, 2-3 minutes. Stir in balsamic vinegar and apricot jam. Let simmer until syrupy, 1 minute. Stir in 1/2 cup water and stock concentrate. Simmer until thickened, about 3 minutes. Remove pan from heat and add 2 Tbsp. butter, gently swirl until melted. Serve this pan sauce drizzled over chicken.