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.
Fold in the blueberries gently so they stay whole.
Stir the cream, lemon juice, and vanilla together, then pour over the dry mix.
Mix with a fork just until a shaggy dough forms; do not overwork.
Turn dough onto a lightly floured surface and gently knead 6–8 times to bring it together.
Pat into an 8-inch round about 1 inch thick. Cut into 8 wedges and transfer to the sheet.
Chill the wedges on the pan for 10 minutes to firm up.
Brush tops with cream and sprinkle with coarse sugar.
Bake 18–20 minutes, until golden at the edges and set in the center. Cool 10 minutes.
Whisk powdered sugar with lemon juice and zest until smooth, then drizzle over warm scones.