Preheat the oven to 400°F. Line 2 baking sheets with parchment paper.

First, make the biscuits. In a large bowl, whisk the flour with the salt, baking powder and baking soda. Using a pastry blender or two knives, cut in the butter until it is the size of small peas. Add the buttermilk and stir until a shaggy dough forms.

Knead the dough on a floured surface until it comes together. Pat the dough 3/4 inch thick. Using a 3 1/2-inch round cutter or large glass, stamp out as many biscuits as possible. Reroll the scraps and stamp out more biscuits.

Transfer the biscuits to the baking sheets and bake for about 30 minutes, until golden and risen, shifting the pans halfway through baking. Let the biscuits cool on the baking sheets.

While the biscuits bake, make the gravy. Melt the butter in a large skillet over medium/low heat. Add the mushrooms and thyme to the skillet. Stir to evenly coat with the butter. Sautee for 15-20 minutes, stirring occasionally.

Add the garlic, salt, and pepper to the mushrooms. Stir and sauté an additional minute.

Sprinkle in the flour and mix until all the mushrooms are evenly coated and the butter is absorbed into the flour. Add the marsala and stir. Slowly pour in the stock and stir until combined with the flour/butter mixture. Break up any clumps of the flour/butter mixture with your spoon.

Pour in the buttermilk. Turn the heat up to medium. Stir to combine. Bring to a simmer. Once simmering, reduce heat to low and cook for 10-15 minutes until mushroom gravy thickens.

When biscuits are baked and slightly cooled, pry a biscuit open and spoon mushroom gravy over the open biscuit.