To make the dough by hand, in a large bowl, stir together flour, sugar, baking powder, and salt. Using a pastry cutter or 2 knives, cut the butter into the flour mixture until the texture resembles coarse cornmeal, with butter pieces no larger than small peas. Add blueberries and toss to mix.
To make the dough in a stand mixer, fit the mixer with the flat beater, and stir together the flour, sugar and salt in the mixer bowl. Add the butter and toss with a fork to coat with the flour mixture. Mix on medium-low speed until the texture resembles coarse cornmeal, with the butter pieces no larger than small peas. Add blueberries and toss to mix.
In separate bowl beat together cream, vanilla, and egg. Slowly pour into dry ingredients, stirring with rubber scraper until dough forms. Knead just until it comes together, 3 or 4 times. Don’t overhandle.
Divide dough in eight even pieces and place on a ungreased baking sheet. Sprinkle with a bit of coarse sugar, if desired.
Bake in preheated oven 20 minutes or until scones are a light golden color. Serve warm.