Sunday Brunch: Marion Cunningham's Oatmeal Pancakes

INGREDIENTS

• 2 cups buttermilk
• 2/3 cup uncooked oats, steel-cut or old-fashioned rolled
• 1 egg
• 2 tablespoons brown sugar
• 1 1/2 ounces (about 1/3 cup) all-purpose flour
• 1 1/2 ounces (about 1/3 cup) whole wheat flour
• 1 teaspoon baking soda
• 1/2 teaspoon kosher salt
• 2 tablespoons (1/4 stick) unsalted butter, melted, plus a little extra for the griddle