Preheat the oven to 425 degrees.
In a large bowl, whisk together the flour, sugar, baking powder and salt. Set aside.
Grate the entire stick of cold butter into small pieces. Add the butter to the flour mixture and mix until little pieces of butter are evenly distributed throughout. Alternatively you can "cut" the butter into the flour mixture using a pastry cutter into pea sized shapes.
Mix together the eggs, heavy cream and milk in a liquid measuring cup. Pour into the butter/flour mixture and mix together until it is just combined and forms a ball.
Turn the dough out onto a countertop or pastry mat and knead two or three times. Cut the dough into two equal sections. Let rest while you mix together the filling.
To a small bowl, mix together the scone filling: brown sugar, powdered sugar, flour, ground cinnamon, heavy cream and vanilla extract. Set aside.
Lightly flour both balls of dough. Roll both balls out into equal sized 8 inch circles. Spread the cinnamon scone filling on top of one of the circles, leaving a little gap on the edges.
Place the other 8 inch circle of dough on top of the cinnamon filling, sandwiching the scone dough together. Pinch the seams closed.
Cut the dough into 8 triangular sections and place on a parchment lined baking sheet.
Bake scones for 14-16 minutes until baked through and a little brown on top.
While the scones bake, mix up the glaze. Whisk together powdered sugar, heavy cream and vanilla extract. After the scones have cooled a bit, top each scone with glaze. Sprinkle colorful sanding sugar on top of the scones. Enjoy!