In a large bowl, mix together 3 cups of bread flour, 2 teaspoons of sea salt, and 1 packet of active dry yeast. Gradually stir in 1 1/4 cups of room temperature water until combined. Cover the bowl with plastic wrap and let it sit at room temperature for 8 to 12 hours.

Preheat your oven to 400°F (200°C). Slice 1 medium onion thinly and sauté in a skillet with 2 tablespoons of olive oil until soft and translucent, about 5-7 minutes. Add a few sprigs of fresh thyme during the last minute of cooking. Set aside to cool.

Wash and slice 2 small firm potatoes into thin rounds. Toss them in a bowl with 1 tablespoon of olive oil, sea salt, pepper, and a few leaves of minced fresh thyme. Spread the seasoned potatoes on a baking sheet and roast in the oven for about 15 minutes until fork-tender and lightly golden.

Preheat a cast iron skillet over high heat for about 5 minutes until very hot. Lightly flour your hands and the countertop, then scrape the risen dough out of the bowl. Divide it into two portions and shape each into an 8-inch round.

Carefully place one dough round in the hot skillet and broil in the oven for approximately 3-4 minutes until lightly browned on the bottom and puffed up. Remove and repeat with the second round.

Brush each crust with olive oil mixed with minced garlic. Distribute the sautéed onions and roasted potato slices evenly over the crusts. Crumble blue cheese on top and return to the broiler for an additional 3-5 minutes until the cheese is bubbly and melted.