Peel the onions. Cut off the top of each onion to create a flat surface for browning. Trim the root ends. If any of the onions are noticeably larger than the rest, peel off an outer layer so that they are closer in size.
Heat an ovenproof frying pan large enough to hold the onions in a single layer over medium heat.
Add the vegetable oil and heat until warm. Add the onions and cook until browned, swirling the pan from time to time for even browning, about 5 minutes.
Turn the onions over and cook for another 5 minutes. Add garlic, thyme, and honey to the pan. The honey will bubble up. Once it stops, ad the chicken stock and swirl the pan to incorporate. Increase the heat to medium-high and bring just to a boil.
Transfer to the oven and cook for 15 minutes, or until the onions are tender and the liquid has reduced to a thick glaze. Season to taste with salt and pepper. Transfer the onions to a serving dish and spoon the glaze over the top.