Preheat the oven to 425°F. Line a baking sheet with parchment paper.
Whisk flour, sugar, baking powder, baking soda, and salt in a large bowl.
Cut in the cold butter with a pastry cutter until the mixture looks like coarse crumbs with pea-sized bits.
Fold in the blueberries to coat them lightly with the dry mixture.
Stir buttermilk, vanilla, and lemon zest together, then pour over the dry ingredients.
Mix gently with a spatula until just combined; the dough should be thick and sticky.
Drop 8 equal mounds of dough onto the sheet using a large spoon or scoop, spacing them apart.
Brush the tops with cream and sprinkle with coarse sugar.
Bake 12–15 minutes until puffed and golden at the edges. Cool 5 minutes before serving.