Heat oven to 400°F. Line a baking sheet with parchment.
Whisk flour, sugar, baking powder, salt, and lemon zest in a large bowl.
Cut in the cold butter until the mixture looks like coarse crumbs with pea-sized bits.
Gently fold in blueberries so they stay mostly whole.
Stir vanilla into the cold cream. Make a well in the dry mix and pour it in.
Mix with a fork just until a shaggy dough forms. Do not overwork.
Turn dough onto a lightly floured surface. Press together and pat into a 7–8 inch round, about 1 inch thick.
Cut the round into 8 wedges and transfer to the prepared sheet, spacing slightly.
Brush tops with cream and sprinkle with coarse sugar.
Bake 16–19 minutes until golden at the edges. Cool 10 minutes before serving.