Line two large baking sheet with baking parchments.
Mix the flour, baking powder, sour cream, one egg, melted butter, half of grated cheese and salt. Stir until become a dough. I usually use a stand mixer for making a dough. The dough should be nice and smooth and non-sticky.
Preheat the oven to 190℃ (375°F).
In a small bowl beat one egg lightly.
Roll the dough 1/2-inch-thick on the lightly floured surface.
Brush all over the rolled dough with beaten egg.
Make two single-folds. At first fold up the thirds of dough and fold down the thirds of dough, much like a letter is folded to fit into an envelope. Then fold the thirds of dough to left and fold the thirds of dough to right (cover the previous folding).
Roll the dough 1,5-cm-thick (1/2-inch-thick), brush the dough with egg and make two single-folds again.
Roll the dough 2,5-cm-thick (1-inch-thick). Make a shallow cross-hatched pattern with a sharp knife all over the dough surface. With a floured cutter, stamp out rounds with a 4,5-cm- (1 3/4-inch-) diameter.
Brush every biscuits with egg and sprinkle the cheese on top. Press it very gently to stick to the egg.
Arrange the biscuits on the baking sheet and bake for 20 minutes until nicely browned on their tops and bottoms.