Place butter in freezer for about 20 minutes. Preheat oven to 425°F, and line baking sheet with parchment. Mix together flour, baking soda, baking powder, sugar and salt in a mixing bowl.
Use a cheese grater to grate the semi frozen butter into flour. After you have grated about half the stick, use a fork to fluff the pieces of butter into the flour mixture, coating them with flour. Finish grating butter and repeat.
Beat/whisk cold egg in a small bowl or cup, add vanilla to beaten egg.
Create a well in the center of the flour and butter mixture, and pour egg mixture plus ⅔ cup cold heavy cream into the well. Use a fork to begin to incorporate the dry ingredients into the wet. Use the fork until dough has mostly come together. There might be some dry bits at the bottom, this is okay. Either use your hands, or a bowl scraper to bring the dough more together, folding it over on itself a few times and incorporating the dry bits of flour into the folds.
Turn dough out onto lightly floured surface and pat out into a circle or square, dough being roughly 1 inch thick. It’s fine if the dough is thicker, erring on the side of too thick vs too thin is better. Lightly flour a knife or bench scraper. Cut the dough into equal quarters, and then half each quarter. When cutting, cut straight down then pull straight back up, do not drag cutting utensil through the dough.
Transfer dough to parchment or silpat lined baking sheet, placing scones about 1 inch apart. Placing them close together allows them to get a little more rise. You can place them closer, however they may bake into each other. If you are working in a particularly warm kitchen, (or even if you aren't), place the scones in the freezer for about 10-20 minutes before baking. You want the butter in the scones to be cold when placed in the oven so that they create steam and give your scones rise instead of spreading out.
Just before baking, brush the top of each scone with heavy cream, and sprinkle with demerara sugar. Place in the oven, reduce the temp to 375°F and bake for about 25 minutes, or until the tops are lightly golden brown.
Scones are best eaten the first day, when warm. To reheat, place scone inside aluminum foil and reheat in oven, air fryer or toaster oven at 350 for about 6-8 minutes.
