In a large bowl, combine the flour, baking powder, salt, and sugar. Add butter and mix using a pastry cutter, two forks, or even your hands, until coarse, pea-sized crumbs appear.
Mix the cream and egg together in a small bowl. Slowly add the cream mixture to the flour mixture and mix until the dough just holds together (here you have to be flexible about the amount of cream to add as the actual amount will depend on the humidity of the day). Squeeze a small amount of dough between your fingers and if it is very crumbly, add more cream, 1 tablespoon at a time (2 tablespoons maximum). If the dough is too wet, you can knead in more flour when you turn out the dough. Remember, do not over mix the dough (you want to keep that butter cold and separate from the flour).
Turn dough out onto a lightly floured surface and push together into a rough ball. Knead a few times to combine (if you're adding any mix-ins to the dough, here's when you'd add them in). Gather the dough, and flatten into a disc or a rectangle about 1" high, cover with plastic wrap, and refrigerate at least 20 minutes or up to overnight.
Preheat the oven to 400°F.
Once the dough is chilled, cut the disc into wedges or the rectangle into squares (if cutting the rectangle into squares, trim the outside edges of the dough first so that the scones can rise evenly). Alternatively, use a biscuit cutter to cut out shapes (gather and cut the leftover dough again as needed, but hopefully not more than 2 times).
Place the scones about 2-inches apart on a half baking sheet pan covered in a Silpat or parchment paper. Brush the tops of each scone with cream and sprinkle some coarse sugar on top.
Bake at 400°F for about 20 minutes or until golden brown.
Cool on pan for 2 minutes, then move to a cooling rack. Drizzle icing (if using) on top while the scoes are cooling. Let the icing set.
Serve warm or at room temperature...pair them with lemon curd and clotted cream for a lovely combination. Enjoy!