Cube the butter and place in freezer.
Whisk together dry ingredients. If you're making lemon scones - zest the lemon into the sugar before adding it to the dry ingredients. Rub the zest into the sugar to release its oils. Add sugar/zest mixture to the rest of the dry ingredients.
Cut in the butter into the dry ingredients using your hands or a pastry cutter. I almost always just use my hands for this. Place in the freezer intermittently if needed if it warms up too much.
Once the mixture is crumbly and there's still a few nice shards of butter in there - add in the sour cream, heavy cream, and vanilla. Mix with a spatula until it starts coming together.
Turn out the dough onto a clean surface and add your blueberries. Work the dough with your hands until it all comes together. Don't knead it or overwork it - just gently coax the dough together. Add more cream if needed if it's too dry.
Form the dough into a disk and cut it in half. Stack the halves and press down. Do this twice. It helps create some layers to help your scones stay tall.
Form into a final disk around 8-10 inches in diameter. Cut into 6 trigangles.
Separate onto a baking sheet and brush with milk. Top with blueberries and some coarse sugar.
Set in fridge or freezer while oven preheats to 400℉. Bake for 20-28 minutes. The scones should look just set and slightly golden on the outside.
Cover in glaze if you'd like them to be sweeter and enjoy!!