Pre-heat oven to 425 degrees.
Pat the chicken dry and season it with thyme, salt, pepper and pepper.
Heat butter in a large skillet over medium-high heat, until foaming. Add chicken, skin side down, and cook without moving it until well browned and crisp, about 8 minutes total, lowering heat if it starts to smoke excessively. Flip chicken and brown lightly on second side, about 3 minutes. Transfer chicken to a large plate and set aside.
Stir in vinegar and honey until combined, all the shallots, season with salt and stir until the shallots are all coated. Cook shallots until they begin to brown evenly, about 10 minutes, then turn the heat off.
Nestle chicken back into pan, pushing the shallots aside so that they chicken skin remains exposed. Add the thyme sprigs. Transfer pan to oven and roast, uncovered, for 15 minutes. Add the grapes to the pan, on top of chicken, and roast for an additional 15 minutes.
Remove from the oven and set chicken aside while you reduce the pan sauce. Place pan on stovetop over medium heat, until sauce is thickened and reduced, about 8-10 minutes. Taste sauce and season with salt and pepper.
Serve with the sauce drizzled over the chicken thighs, alongside the caramelized shallots and roasted grapes.