Place all ingredients in a VERY large bowl, and stir gently until combined. Store in an airtight container in a cool, dry location.
To make muffins:
Preheat oven to 400F degrees. Spray two muffin tins with non-stick spray, or prepare with paper liners.
In large bowl, beat 4 eggs. Add 3 teaspoons vanilla, 2 cups water and 3/4 cup vegetable or canola oil.
Stir in 5 1/2 cups of dry muffin mix, just until moistened. Gently add in any mix-ins (see notes or find the full list at grouprecipes.com).
Spoon into prepared muffin tins, making sure to fill each muffin cup to the top. Optional: Add topping(s).
Bake at 400F for 18-20 minutes until tops are golden brown and toothpick inserted into muffin comes out clean.
Notes
Here are a few of the mix-in options we use most often:Blueberry - add 2 cups fresh or frozen berriesStrawberry - add 2 cups fresh or frozen chopped berriesMixed berries - add 2 cups combo of fresh or frozen chopped berriesLemon Poppy Seed - add 2 pkgs (3.4oz) lemon flavor instant pudding, 2 tablespoons poppy seeds, omit 1 cup water and replace with 1 cup lemon juicePumpkin - add 2 cups solid pack pumpkin and 1 tablespoon pumpkin pie spice (add 1/2 cup chopped nuts if desired)Cream Cheese topping - mix 2 8oz pkgs softened cream cheese with 1/2 cup sugar and 2 eggs, then drop by rounded tablespoon onto top of each muffin before baking