Preheat oven to 375 degrees.
Mix flour, baking powder, and salt.
Using a pastry cutter, two knives, or your fingers, mix in the butter until it is very crumbly. Crumbs should be the size of small peas.
Drizzle milk, or half and half if you're using it, over the mixture slowly, and gently fold in the sides of the flour mixture until you have a wet, sticky dough. Depending on your flour mixture, you may need a little more, or a little less, milk to form the dough. Be careful to add it just a little at a time, though, because you want to use just enough. If you get too much milk, the dough will be too wet.
Add in the 1 cup of blueberries. Fold the blueberries in very gently, and do not over handle he dough once they are incorporated.
Turn onto a floured surface, and pat out the dough to about 1/4 to 1/2 inch thick.
Using a biscuit cutter or a mason jar, cut out your biscuits and place them on a baking sheet. I use a nonstick pan, so I do not grease my pan. I do, however, recommend using some wax paper or parchment to protect your baking sheet, as the blueberries will pop and juice will run once they are in the oven.
Brush the tops of the biscuits with milk or half an half, to help them get that nice, golden brown top once they are baked.
Place biscuits in the oven and bake for 18-25 minutes, or until the tops are golden brown and the biscuits are baked through.
While your scones are baking, combine lemon juice, powdered sugar, and milk in a bowl, and use a whisk to combine the ingredients into your icing.
When biscuits are done baking, transfer to a wire rack to cool. Brush about a tablespoon of icing over the tops of your biscuits. May use more or less icing to taste.
Serve warm. Will store in an airtight container for a day or two, but if you plan to eat them later than that, freeze them after they have come out of the oven and cooled, and before icing them.