Step 1Line 2 baking sheets with parchment paper.
Step 2In a large bowl, whisk together the flour, salt, sugar and baking powder. Grate the frozen butter over the flour mixture using the larger holes of a box grater. Once all of the butter has been grated, place the bowl into a freezer to chill the butter before mixing.
Step 3When the butter is frozen, gently rub the mixture between both hands, or use a fork or pastry cutter, to incorporate the butter into the flour until the mix slightly resembles a streusel. Return the mixture to the refrigerator to keep cold.
Step 4In a separate bowl, whisk together the eggs, buttermilk and creme fraiche. Create a well with the dry ingredients and add the liquid mix into the center. Using a fork, pastry cutter or your hands, fold the liquid into the dry mixture just until the flour is hydrated. Turn the mix onto a floured surface and gently pat it down to a 1-inch-thick block.
Step 5Portion each biscuit using a 3-inch square or round cookie cutter. Place 6 biscuits in a pan, spacing them a couple inches apart (the biscuits will spread as they bake). Place the pans in the refrigerator for 20 minutes to chill the formed biscuits. Meanwhile, heat the oven to 425 degrees.
Step 6Remove 1 tray of biscuits from the refrigerator. Brush the tops with buttermilk and sprinkle kosher salt on top of each. Bake until the biscuits are puffed and golden on top, about 25 minutes, rotating halfway through for even baking and coloring. Repeat with the second tray.