Preheat oven at 375ºF (190ºC).
Have ready oven trays or cookie sheets.
I use the processor at the beginning, but you can do it by hand.
Put flour, salt, cheese and baking powder in the bowl of the food processor or a large bowl.
Pulse a few times to mix or mix with spoon or spatula.
Scatter cold diced butter and pulse until it is the size of peas.
By hand start mixing the butter into the flour with the palms of your hands. It wil take a bit since the butter is cold.
If using the processor transfer the mixture to a large bowl.
Add pepper and chives. Mix a bit.
Mix together sour cream and milk in a small bowl and add to the flour mixture.
Mix with a fork until most of the dry ingredients are mixed. There will be dry patches, that is fine.
Now, you can give it a few turns inside the bowl with your hand or do it on the counter.
The dough should come together just barely, be careful not to overwork it as it will soften the butter too much and that will prevent the scones from rising properly. It should have some dry spots. It doesn’t need to come together like pie dough.
Give it a few folds onto itself and pat it about 1 ½ to 2 inches thick.
Using a round cutter dipped in flour, cut circles. See Notes below for comment on cutter size. Continue dipping in flour to prevent sticking every time you cut a scone.
Put them on the baking sheets spacing a bit, and put them in the freezer for 5 minutes.
Make sure the oven is at the right temperature and bake them for about 15 minutes, until puffed and no longer creamy inside. You might need to open one and check.
The bottoms will be golden but the rest of the scone not so much.
Let them cool until warm and enjoy.