Oatmeal Cookie – 2 cups (172 g) old fashioned or rolled oat – 2 cups (240 g) all purpose flour – 2 teaspoons ground cinnamon – ¼ teaspoon ground nutmeg – ¾ teaspoon baking soda – ½ teaspoon salt – 1 cup (226 g) unsalted butter melted and cooled – 1 cup (200 g) light brown sugar – ½ cup (100 g) granulated sugar – 1 large egg (US), room temperature – 1 large egg yolk (US), room temperature – 2 tablespoons (30 ml) molasse – 2 teaspoons (10 ml) vanilla extract Icing for Oatmeal Cookie – 2 cups (240 g) powdered sugar – 3 - 4 tablespoons (45 - 60 ml) milk or water