Preheat the oven to 450°F.
Peel the potatoes and place them in a bowl of salted cold water to prevent them from turning brown while peeling the remainder.
Pat the potatoes dry with a paper towel.
Slice the very ends of the potato off to give them flat sides. Then cut the potato into 1-inch discs or cylinders.
Pat the potato pieces dry with paper towels and season each side with salt and pepper.
Roughly chop the garlic into halves or quarters, but not too small.
Add the avocado oil and two tablespoons of butter to a cast iron skillet (or any oven safe skillet) and warm over medium high heat.
Once hot, place the cut potatoes in the skillet to pan fry. DO NOT TOUCH for 4 minutes, allowing them to get a good sear.
After the 4 minutes, give the skillet a good shake to prevent the potatoes from sticking. Continue to move the pan (and potatoes) around for another 3-4 minutes. Lower to medium heat if they are browning too quickly, as you do not want them to burn.
Once the potatoes are golden brown, use a thin spatula like a fish spatula to flip potatoes to the other cut side down.
Add the remaining butter and once melted, add the garlic cloves and fresh thyme.
After the thyme and garlic become fragrant (30 seconds to 1 minute), add the chicken stock and give the skillet a good shake to incorporate the butter, herbs, and stock. Bring the stock to a boil.
Place the cast iron skillet into the preheated oven and bake for 25 minutes or until a small knife blade tip can be easily inserted into the center.
Discard the garlic and thyme sprigs. Transfer to a serving platter and pour the sauce over the potatoes, or serve directly from the pan.