Preheat oven to 425°F. Line a sheet pan with parchment paper.

In a large bowl, whisk together flour, sugar, baking powder, and salt. Cut in the butter until small crumbs form, about the size of peas.

Fold in chocolate chips.

Separately, whisk together egg, sour cream, and vanilla. Using a fork, make a well in the dough and gently incorporate egg mixture until just blended. Bring the dough together.

On a lightly floured surface, shape dough into an 8 inch round about 1 inch thick. Cut into 8 wedges and place on baking sheet.

Brush top of scones with heavy cream and bake until golden brown, 12 to 14 minutes.