The batter keeps in the refrigerator up to one week, so you can have freshly-baked muffins on your table in next to no time. For variety, add currants, dried cranberries or other dried chopped fruit before baking.
Stir flour, sugar, baking soda and salt in large bowl to blend; mix in cereal; whisk buttermilk, oil, eggs and zest in medium bowl to blend; mix into dry ingredients; cover and refrigerate; this mixture can be kept in the refrigerator for up to 1 week; it will thicken over time.
Preheat oven to 400F; line 18 muffin cups with liners.
Spoon 1/3 cup batter into each muffin cup; bake until tester comes out clean, about 15-20 minutes.