• Preheat oven to 350℉. Prepare two baking sheets by lining with parchment paper or silicone baking mats.
• Gather the ingredients so that you have everything close at hand on the counter or table.

Prepare the Ingredients

• In a food processor or blender, grind 3 cups old-fashioned oats to a coarse flour.
• If desired, chop 1 cup raisins, using a Chef’s knife or wavy chopping blade, and cutting board.

Make the Cookie Dough

• In medium bowl, combine 4 cups all-purpose flour, ground oats, 3 1/2 teaspoons baking powder, 1 teaspoon baking soda, 1 teaspoon salt, 2 1/2 teaspoons ground cinnamon, and 1 1/2 teaspoons ground nutmeg.
• Cream together 2 cups butter (softened), 1 1/2 cups granulated sugar, and 1 1/2 cups brown sugar in a large mixing bowl.
• Add 4 large eggs one at a time. Stir in 1 tablespoon vanilla extract.
• Gradually add flour-oat mixture, scraping the bowl as needed. Add in the chopped raisins.
• Drop by tablespoonfuls onto prepared baking sheets. Bake in preheated oven for 11-15 minutes until edges are golden brown. Cool on wire rack.

Prepare the Vanilla Icing

• In a small bowl, whisk together 2 cups powdered sugar and 3-4 tablespoons whole milk until smooth. Drizzle over cooled cookies and allow to set. Makes 5-6 dozen.