Refrigerate or freeze a metal bowl for 5 minutes to get it cold.
Chop the drained maraschino cherries into small pieces using a food processor or knife. Place the cherries in the refrigerator. 16 ounces maraschino cherries
Preheat the oven to 425ºF.
In the refrigerated bowl, add the flour, baking soda, cream of tartar, sugar and salt. Whisk together, then place the bowl back in the fridge. 2 3/4 cups all-purpose flour, 1 rounded teaspoon baking soda, 2 rounded teaspoons cream of tartar, 2 tablespoons granulated sugar, dash salt
Grate the cold butter with a box grater. Using a pastry cutter, cut the butter in with the flour mixture until the butter is mostly mixed in. It is okay if there are small pieces of butter. 1/2 cup plus 1 tablespoon cold salted butter
Make a well in the flour, in the center of the bowl. Add the buttermilk and beaten egg to the well. Using a wooden spoon, mix the wet ingredients into the dry ingredients. Add the cherries and mix just until blended, being careful not to overmix. 1 cup buttermilk*, 1 large egg
Put about 1/4 cup of flour on the cupboard. Turn the dough out onto the floured counter. Flour the top of the dough. Gently form an 8" disk that is about 11/4 inches thick.
Use a floured knife to cut the disk into 8 triangles as if you were cutting a pie. Place the scones on a greased cookie sheet, or a nonstick baking mat.
Bake immediately for 12-14 minutes. Allow the scones to cool for 10 minutes and prepare the glaze.
In a bowl, melt the butter. Add the sifted powdered sugar and vanilla. Mix well. Add the cherry juice, 1-2 tablespoons at a time, until you can easily spoon the glaze over the scones. 2 tablespoons salted butter, 2 cups powdered sugar, 1 teaspoon vanilla extract, 1/3 cup reserved cherry juice
Immediately after glazing the scones, sprinkle with chopped pistachios. 1/3 cup chopped pistachio nuts
Notes
You can make your own buttermilk by adding 1 teaspoon of white vinegar to whole milk. Allow this to sit for 3 minutes. It's best to use whole, high fat milk.
Some maraschino cherries do not have red food dye. Which is great, but when the cherries bake into the scones, they lose their color and ended up blending into the dough. As you can see in the pictures, you can't see the bits of cherries, but they're there! If you want the pink/red bits of cherries, find maraschino cherries with the red food dye.
*With this recipe, it is important to work quickly. The ingredients need to stay cold. If the oven isn't quite heated when the scones are ready to bake, place the pan of scones in the refrigerator until the oven is heated.