It does not matter if you want blueberry, chocolate chip, or any other type of muffin, it's possible to make them scratch. You need to start with a basic muffin recipe. This option with cranberries was adapted from "The Everything Classics Recipe Book" by Lynette Rohrer Shirk.
Preheat the oven to 400 degrees Fahrenheit. Grease a 12-cup muffin tin or line the holes with paper muffin cups.
Mix the flour, sugar, baking powder, and salt in a large mixing bowl.
Combine the eggs, milk, butter, and vanilla in another bowl using a whisk.
Combine the ingredients in one bowl, then add the cranberries (or whatever fruit you want to use).
Distribute the muffin batter evenly into the 12 muffin cups.
Bake the muffins for 15 minutes, or until they are golden brown. Let them cool at least 20 minutes before serving.