Start by dicing your cold unsalted butter into 1/4-inch cubes and place them in the freezer to chill.

In a stand mixer bowl, combine all-purpose flour, granulated sugar, baking powder, baking soda, kosher salt, black pepper, minced sage, and grated Gruyere cheese. Whisk these together.

Slowly add the chilled butter cubes to the bowl and mix until the mixture resembles coarse crumbs.

Gradually pour in the cold buttermilk and heavy cream while mixing, until the dough just starts to come together.

Lightly flour your work surface, transfer the dough, and gently press it into an 8x11 inch rectangle. Fold into thirds like a letter, repeating this three more times, then roll into a 9-inch square, about 1 inch thick.

Cut the dough into 9 squares or preferred shapes, place on a parchment-lined baking sheet, and refrigerate for about 45 minutes.

Preheat your oven to 450°F. Brush the tops of the chilled biscuits with heavy cream and sprinkle with flaky sea salt. Bake for 18-20 minutes until puffed and golden brown.