1. Preheat oven to 400°.
2. Combine first 5 ingredients in a medium bowl; make a well in center of mixture. Combine buttermilk and next 4 ingredients, stirring well; add to dry ingredients, stirring just until dry ingredients are moistened.
3. Spoon batter into muffin pans coated with cooking spray, filling three-fourths full. Bake at 400° for 15 minutes. Do not remove muffins from pans.
4. Combine marmalade, lemon juice, and water in a small saucepan; place over low heat until melted, stirring often. Drizzle glaze evenly over warm muffins in pans. Remove from pans, and cool completely.
Glazed Citrus Mini-Muffins: Prepare batter as directed. Spoon into miniature muffin pans; bake at 400° for 14 minutes. Drizzle glaze over warm muffins in pans. Remove from pans, and cool completely.