Preheat oven to 375°F. Spray a baking sheet with cooking spray or line with a piece of parchment paper.
Combine the first four ingredients in a medium bowl, stirring with a wire whisk. Set aside.
Combine flour, baking powder, and salt in a large bowl, whisking to combine. Cut in the chilled butter with a pastry blender (or 2 knives) until the mixture resembles coarse meal.
Gently fold in chocolate chips.
Add buttermilk mixture to dry mixture, stirring just until moist.
Place dough onto a floured surface and knead lightly four times with floured hands. Form dough into a 9-inch circle onto the baking sheet, about ¾-inch thick.
Using a knife, cut dough into 12 wedges all the way through.
Brush egg white over dough and sprinkle evenly with sugar.
Bake until golden, about 18 - 20 minutes. Serve warm.
Notes
If you don’t have buttermilk, you may mix 1 cup regular milk with 1 tablespoon white vinegar. Let sit for 5 to 10 minutes at room temperature before using. For this recipe, you only need ¾ cup of milk/vinegar.Source: Adapted from SkinnyTaste.comYou're Gonna Bake It After Allbakeitafterall.com