Preheat the oven to 425°F (218°C) and line a baking sheet with parchment paper.
In a large bowl, whisk together 2 cups all-purpose flour (spooned and leveled), 1 tablespoon baking powder, 1 tablespoon cane sugar, and 1 teaspoon sea salt.
Grate ½ cup (1 stick) frozen unsalted butter on the large holes of a box grater. Add the grated butter to the flour mixture, toss to coat, then use your fingertips to rub the butter into the flour until the mixture resembles a coarse meal. Work quickly so the butter stays cold.
Pour in ¾ cup whole milk or buttermilk and stir with a wooden spoon until a shaggy dough forms. Use your hands to gently knead the dough in the bowl just until any remaining dry flour is incorporated and the dough holds together.
Turn the dough out onto a lightly floured work surface. Pat or roll the dough into a ½-inch-thick rectangle. Fold the rectangle into thirds (like a letter), then pat or roll it back out to a ½-inch thickness. Rotate the dough a quarter turn and repeat the fold-and-pat step three more times (for a total of four folds), dusting the surface with a little additional flour only if the dough sticks. After the fourth fold, pat or roll the dough one final time to a ½-inch-thick rectangle.
Use a 3-inch biscuit cutter to cut out 6 biscuits, pressing straight down without twisting. Re-roll the scraps as necessary and cut additional biscuits if possible. Place the biscuits on the prepared baking sheet.
Bake for 14 to 16 minutes, or until the tops are golden brown. Let the biscuits cool on the baking sheet for 5 minutes before serving.