In large saucepan, mix milk powder and water.
Heat over medium heat until milk begins to boil (at about 200°F) and starts to steam and turn foamy.
Stir in white vinegar, salt, and butter or oil.
Let mixture sit 10 to 20 minutes or until whey (yellowy liquid) and curds (white clumps) fully separate.
Use strainer with small holes to strain curds (may also use cheese cloth or clean t-shirt).
Let curds sit in strainer about 30 minutes.
Remove any remaining whey by pushing curds against the side of strainer with a spoon.
Transfer Ricotta Cheese to an airtight container and refrigerate.
