Ordinarily, puff pastry is a pretty fussy thing to make from scratch - folding, turning, etc. With a food processor and 3 ingredients, you can crank some out in the comfort of your own kitchen. It's really important to let the dough rest for several hours, or preferably overnight. If not, it will still taste good, but won't puff as well. The recipe calls for butter. I've never used margarine, so use it at your own risk...
1 1/2 cups flour
2 sticks of cold, unsalted butter (1 cup), cut into pieces
1/2 cup sour cream
Measure the flour into a food processor. Add the cut up butter. Pulse until the mixture is mealy looking. Add the sour cream and pulse until it begins to come together in a ball. Divide the dough into 2 pieces. Shape into a ball and flatten slightly to make a rounded disk shape. Wrap tightly with waxed paper or plastic wrap and chill for 6 - 8 hours, or preferably overnight. When ready to use, roll out into the desired shape. Each disk is the equivalent of one puff pastry sheet. The entire recipe is equal to a package of pastry sheets (each package typically contains 2 individually wrapped sheets).
I've used this recipe to make elephant ears, crescent rolls (way better than the canned version), herb twists, crusts for chicken pot pie, and turnovers. It also freezes well.