This homemade muffin mix makes super flavorful, richly textured, crunchy-capped muffins attainable on even the busiest weekdays. And the recipe is endlessly adaptable because of the weights in grams. Don’t have rye flour? Double up on the whole-wheat flour. Have Greek yogurt? Use it instead of sour cream. Even better, the basic recipe lends itself so well, flavor-wise, to virtually any type of add-ins, from fresh fruit to chocolate chunks. See below for a few of my favorite variations. —EmilyC
In a food processor, blitz the oats until they are finely ground.
Combine the oats and all of the other dry ingredients in a large bowl. Whisk until evenly combined. Store the muffin mix in an airtight jar, container, or gallon-sized ziploc bag at room temperature until ready to use. Alternatively, evenly portion the muffin mix into three bags or containers. For one batch of muffins, you'll need 448 grams of muffin mix. (This roughly equals 3 cups minus 1 tablespoon plus 1 teaspoon, but I'd highly recommend measuring by weight.)
For making 1 batch (12) muffins:
Position a rack in the center of the oven and heat oven to 350F. Line a 12-cup muffin tin with paper or foil liners (or generously grease each cup with butter or oil).
Add 448 grams muffin mix to a large bowl; whisk to aerate. In a separate bowl, whisk together eggs, olive oil, sour cream, and vanilla until smooth. Pour the wet ingredients over the dry ingredients, and with a rubber spatula, gently fold just until blended. The batter will be thick; set aside for a few minutes to let the flour hydrate.
Gently fold in optional add-ins (see suggestions below). No need to coat berries or other additions in flour; the nicely thick batter prevents sinkage!
Using an ice cream scoop (or 2 spoons), fill each cup with batter (it should almost reach the top). Sprinkle the coarse sugar evenly over the 12 cups.
Bake until the muffins are golden brown and the tip of a paring knife or toothpick inserted into the middle comes out clean, about 18 to 24 minutes. The middles should spring back lightly to the touch. Let the muffin tin cool on a rack for about 15 minutes, then remove the muffins.
MY FAVORITE VARIATIONS:
For lemon-blueberry muffins: add 1 cup blueberries + the finely grated zest of 1 lemon + 1 tablespoon lemon juice to the batter. (An equal amount of raspberries or blackberries can be substituted!)
For cinnamon-chocolate chunk muffins: add 1 cup chopped dark chocolate (or chips) + 3/4 teaspoon cinnamon to the batter. (Or add 1/4 cup chopped nuts and reduce the chocolate to 3/4 cups!)
For orange, currant, & poppy seed: add 1 tablespoon finely grated orange zest + 1 tablespoon orange juice + 2/3 cup currants + 4 teaspoons poppy seeds.
Or create your own variation with different combinations of fresh fruit, dried fruits, nuts, and spices! As a rule of thumb, I like to stay around 1 cup (total) of mix-ins.