Preheat oven to 400F and pop your butter into the freezer.
In a large mixing bowl, whisk together all the dry ingredients.
In a small mixing bowl, whisk together the wet ingredients until smooth.
Take the butter out of the freezer and grate the cold butter directly into the dry ingredients and whisk periodically so it doesn't clump together.
Pour the wet ingredients into the dry ingredients and fold in with your hands. Once you start to feel a dough forming, dump it out onto a large piece of parchment dusted with flour. Gently form it into a circle (incorporating all dry pieces that may be left) that is about 8" in diameter. Pat it down and cut into 8 pieces using a sharp knife or pizza cutter. and spread the pieces out slightly. Slide a rimless pan under the parchment paper gently lifting onto the pan.
Bake 16-18 min, until golden brown. If you push down gently on the top it should feel a little spongy. Remove from the oven and set aside to cool.
While the scones are baking, make the glaze. Whisk all the ingredients together. Depending on the thickness of your tahini you may need to add a bit of water to thin it out.
Once the scones are cooled, drizzle the glaze overtop and serve. Scones are best eaten the day they're made fresh out of the oven, but they will keep for a couple days in an airtight container. I suggest pouring the glaze on when you're ready to eat.