Preheat the oven to 400°F/200℃.
In a large mixing bowl, whisk together flour, sugar, baking powder, and salt.
Quickly cut butter and lemon zest into the flour mixture, using your fingertips until the mixture resembles coarse crumbs; this might take about 3 to 5 minutes.
Fold the blueberries into the batter. Take care not to mash or bruise the blueberries because their strong color will bleed into the dough.
Make a well in the center of the bowl and pour in the heavy cream and vanilla extract. Stir with hands or rubber spatula until it forms a rough ball; do not over mix, about 1 minute.
Transfer dough onto a floured board or surface; then knead for about 3-4 minutes, just enough for it to come together.
Gently press the dough down into a circle about ¾ thick. Use a very shape knife to cut into 8 wedges (like a pizza).
Separate wedges and place them on an ungreased baking sheet. Brush the top of the scones dough with heavy cream.
Bake at 400°F/200℃ for 15-20 minutes, or until lightly browned. Start checking after 12 minutes.
Remove, let it cool on a wire rack for about 5 minutes, and serve warm.