Preheat oven to 450°F.
Mix together flour, baking powder, sugar, cream of tartar, and salt.
Cut in your grated butter with a pastry cutter or with cold hands until your mixture looks like coarse cornmeal with an occasional pea in it.
Make a well in the center and add the milk, egg, and vinegar.
Stir gently until the dough forms a ball.
Lightly flour your work surface, turn out your dough, and knead about ten times.
Pat your dough out to a circle about ½” thick.
Use a sharp knife to cut the circle into eight equal wedges, like slices of pizza.
Place scones on a baking sheet and bake for 9 minutes.
While the scones are baking, gently wash the pansies in cool water and pat dry.
When the 9-minute cook time is up, remove the pan from the oven but leave the oven on.
Brush the top of one scone with egg white wash.
Place prepared pansies on the coated scone in whatever pattern you choose.
Brush the pansies all over with egg wash. Repeat with each scone.
If desired, sprinkle scones with additional sugar.
Return scones to the oven and bake for another 3 minutes.
Remove the scones from the oven and transfer to a cooling rack.
Once the scones are cool, slather with butter or clotted cream and serve with a pot of tea.