Add 4 cups flour and 500 mL sour cream to stand mixer bowl with the dough hook attached. If you don't have a stand mixer, mix the ingredients with a wooden spoon until it's all together, remove from bowl and knead by hand
Turn on mixer to lowest speed for about 3 minutes, until a dough starts to form
Add 1/2 cup flour and continue to knead with mixer for another minute before adding the last 1/2 cup.
Remove dough from bowl and knead over a floured surface for about 10 (yes, 10) minutes until dough is smooth to the touch, not too sticky
(If your dough is really sticky, add a bit more flour at a time)
Form dough into a ball and cover tightly with plastic wrap, allow to rest on the counter. If you are making your dough a day in advance, rest in the fridge
Put a large pot of salted water on to boil
In the meantime, peel and chop potatoes
Add potatoes to pot of water, lid on
Allow to continue boiling, checking potatoes occasionally with a fork.
Grate entire 450 g block of old cheddar
Once the potatoes are soft enough to mash (easy to pierce with a fork), drain water
Keeping the potatoes in the pot, add garlic powder, pepper and salt The potatoes have to be hot so the cheese melts, so don't cook them ahead of time
Add a couple of handfuls of cheese, begin to mash
Continue mashing and mixing potato and cheese until smooth
Line a couple of baking sheets with wax paper
On a clean, floured surface, roll out about 1/4 of the dough (keep leftovers wrapped in plastic)
Using a glass, or circular cookie cutter with a 3 inch opening, cut circles into the dough
Dough circles should peel off the counter easily
Add about 1 tablespoon of potato cheese mixture to the centre of the dough circle, gently stretching out the circle so you can fold it over the potato, lining up the edges (now, you should have a half circle)
Pinch the edges, leaving no openings. If the dough won't stick, dip your fingers in a bit of water and wet the edge of one side to "glue" them together
Line perogies up on baking sheet, close together but not touching
Once your baking sheet is full, put it in the freezer (Don't freeze the amount you want to eat fresh) and continue filling dough.
Once they are frozen, transfer to airtight containers (I usually just use zip top bags), keeping them in the freezer and pull out as you need. They will keep for quite some time.
I often have leftover potato-cheese... just put it in the fridge, someone will eat it cause it's super tasty.
To cook these fresh, add to a pot of boiling water for about 3 minutes, or until they've been floating for about 30 seconds
To cook these from frozen, add to a pot of boiling water for about 6 minutes, or until they've been floating for about 30 seconds
Toss in some butter so they don't stick together, or I highly recommend transferring to a frying pan with sauteed onion (and some bacon!!)