Preheat oven to 375ºF (190ºC).
Cut cheeses into bite size pieces.
In a small bowl lightly mix egg, sour cream and milk.
In the bowl of a food processor, mix flour, sugar, baking powder and salt. Add cold butter, cut into cubes and pulse until you have a coarse mixture, the butter the size of peas.
Transfer to a large bowl, add wet ingredients and mix with a fork until you have a shaggy mass with some dry patches. Add cheeses and dill and mix some more but just to combine.
Dump onto a lightly floured counter, cut in half and form one of the pieces into a rough rectangle. It doesn’t matter if it’s very irregular and has a dry bit here and there.
Cut scones into triangles with a kitchen knife or dough scraper, or use a round cookie cutter (dip it in flour and make one clean press down, don’t rotate it left and right when cutting, as it will prevent the scones from rising properly).
Repeat with second piece of dough, cutting 6 more triangles.
Transfer to a greased baking pan or lined with parchment paper.
Bake for about 25 to 30 minutes, until golden, dry and cheese has melted and crusted.
Cool for 5 minutes and eat warm.
Store leftovers in the fridge, wrapped in foil. Rewarm for 5 or 10 minutes before eating.
You can freeze the unbaked scones for 1 month, wrapped in foil. Bake the frozen as directed above.