Preheat your oven to 400˚F (200˚C).
In a large bowl, mix together all-purpose flour, granulated sugar, baking powder, Meyer lemon zest, and salt until well combined.
Cut chilled unsalted butter into your dry mixture using a dough blender or two forks until it resembles coarse crumbs with no pieces larger than a pea.
In another bowl, whisk together heavy cream, egg, Meyer lemon juice, and vanilla extract until fully blended. Pour this mixture into your dry ingredients carefully and stir gently until just combined.
Turn your dough onto a floured surface and lightly knead it just enough to bring it together before pressing it into a disc about 3/4 inches thick. Cut into eight equal slices before transferring them onto a prepared baking sheet brushed lightly with heavy cream.
Bake in your preheated oven until golden brown for about 12 minutes. Once done, let them cool on the baking sheet for five minutes before transferring them to a wire rack to cool completely before glazing if desired.