In a medium bowl, whisk together flour, sugar, baking powder, salt, and cream of tartar.
Cut in butter with a pastry cutter or fork until mixture forms coarse crumbs. It will look similar in texture to wet sand.
Make a small well in the center, and pour in milk and buttermilk. Toss with a fork until milk is incorporated and a shaggy dough forms.
Turn out dough onto a floured work surface. Sprinkle a little extra flour on top. Knead gently 5 or 6 times. Do not overwork the dough or your shortcakes will be tough.
Pat dough into a ½-inch thick rectangle. Cut with a 3-inch round biscuit or cookie cutter dipped in flour to prevent sticking. Gather scraps and pat out again if necessary.
Preheat the oven to 425°F. Line a baking sheet with a silicone mat or parchment paper.
Place shortcakes on the prepared baking sheet. Bake for 15-18 minutes, or until golden brown. Cool on a wire rack.
Strawberry Filling
In a medium bowl, gently toss berries with sugar. Allow to macerate about 30 minutes. Set aside.
Black Pepper Whipped Cream
In a small saucepan whisk together sugar and water. Bring to a low boil.
Reduce heat to medium low, and simmer for 10-12 minutes, or until syrup becomes slightly thickened.
Stir in peppercorns, cover and steep 20 minutes. Drain through a fine mesh strainer or cheesecloth to remove pepper. Allow to cool, and chill in a covered container until ready to use.
Chill a metal bowl and beaters for the whipped cream.
Once the bowl is chilled, beat together whipping cream and 2 Tbsp black pepper simple syrup until peaks form, about 3 to 5 minutes. Chill until ready to serve.
