How to Make It
In a large bowl, whisk the flour with the masa, sugar, salt, baking powder and baking soda. In another bowl, whisk the eggs with the buttermilk and melted butter, then whisk into the dry ingredients just until incorporated; add a tablespoon of buttermilk if the batter is very thick.
Preheat a griddle and brush lightly with oil. Scoop 1/3-cup-size mounds of batter onto the griddle, allowing them to spread on their own. Cook over moderate heat until bubbles appear on the surface, about 4 minutes. Flip and cook the pancakes until they are risen and golden brown on the bottom, about 2 minutes longer. Transfer to plates and serve hot with butter and maple syrup.
Masa harina (nixtamalized corn flour) is available at supermarkets, specialty food shops and online at mexgrocer.com.