Peel the potatoes and slice into 1/2" rounds. Place the potato rounds into a large pot and cover with cold water. Season generously with salt. Add the thyme and bring to a gentle simmer over medium heat.
Cook potatoes until just tender, taking car not to overcook. They should be easily pierced with a fork - about 25 minutes.
Drain the potatoes. Return to pot.
Discard thyme "branches", making sure that the thyme leaves are left in the pot with the potatoes.
Preheat oven to 350℉
While oven is preheating, cut the bacon into 1/4" lardons. Add it to a 10" cast iron skillet and heat over medium-high until the fat starts to render. Once fat has begun to render, turn the heat down to medium and continue to cook until the bacon is cooked, but not crisp. This should take about 5-7 minutes.
While bacon is cooking, peel and thinly slice the onion.
If there is excessive rendered fat, drain off all but 1/4 cup - BUT - if the bacon didn't release much fat, add 1-2 Tablespoons of butter to the skillet. Add onions and season with dried thyme, salt, and pepper. Stir frequently until the onions have softened, but not browned. This should take 8-10 minutes.
Add the Pressed Garlic. Stir to combine and cook until fragrant, about 1 minute.
Add white wine. Scrape any bits that have stuck to bottom of pan. Stir and cook until the wine has mostly cooked off, about 1-2 minutes.
Add Heavy Whipping Cream. Cook until it begins to simmer.
Scrape the onion-bacon mixture into the pot with the potatoes. Stir gently to thoroughly combine.
Transfer the potato mixture back into the cast iron skillet.
Cut the Brie into roughly 1/2" slabs. Do this by laying the round on your cutting board and cutting it in half - into two half-moons.
Next stand each half-moon on edge and slice each half-moon into two half-moons. You will end up with four half-moons.If you would like, you can slice the rind off at this point as well.
Arrange the cheese on top of the potatoes, rind-side up if you left the rind on.
Set skillet on a rimmed baking sheet and place it in the oven. Bake until the cheese is melted, bubbling, and lightly browned on top, about 40-45 minutes.
Slice, scoop, and ENJOY!