Prep your potatoes, saving the scraps for another dish. Smash your garlic and set aside.
Arrange oven rack in the middle of the oven at 400°F.
Heat oil in a pan over medium-high heat. Add potatoes, cut side down and brown for 2-3 minutes. Flip and reduce the heat to low. Add butter, garlic, thyme, and rosemary. Cook until the butter is foaming and starts to brown, 2-3 minutes. Add chicken stock so potatoes are half submerged. Bring to a simmer.
Transfer to the oven and bake until the potatoes are fork-tender and lightly browned on all sides, 15-20 minutes. Remove from the oven and serve.