BISCUITS
1 large egg
¼ cup buttermilk
1 tsp. vanilla extract
¼ cup heavy cream, plus more for brushing
1¾ cups all-purpose flour
¼ cup granulated sugar
2½ tsp. baking powder
½ tsp. Diamond Crystal or ¼ tsp.
Morton kosher salt
¼ tsp. baking soda
6 Tbsp. chilled unsalted butter, c...