Put the butter out of the fridge before starting the process. Butter needs to be soft, but not too soft.
1 cup Butter
Preheat the oven to 350°, and line two baking sheets with parchment paper. Set aside.
Sift all dry ingredients, and set aside.
1½ cups All-purpose flour, ½ teaspoon Baking powder, ½ teaspoon Baking soda, ½ teaspoon Salt, 1 teaspoon Cinnamon
Set your mixer on paddle attachment. Cream the butter with two sugars. Scrape down the bowl as needed. This will take about two minutes.
1 cup Brown sugar, packed, 1 cup Butter, ½ cup Granulated sugar
Add the eggs, one at a time, and mix after each one. Add the egg yolk, and the vanilla extract.
2 Eggs, large, 1 Yolk, 1 tablespoon Vanilla extract
Add the dry ingredients, and mix just until the flour is incorporated.
1½ cups All-purpose flour, 1 teaspoon Cinnamon, ½ teaspoon Baking powder, ½ teaspoon Baking soda, ½ teaspoon Salt
Fold in the oats, raisins, and walnuts, and mix until all distributed evenly.
3 cups Rolled oats, 1 cup Raisins, 1 cup Chopped walnuts
Scoop the dough into small balls, the size of a small tangerine, and place them on the baking sheets. Leave a 2-inch space between them.
Bake at the 350° oven for 12 minutes. Until the edges of the cookies are set. The center of the cookies should look undercooked. They keep baking after they are removed from the oven.
Place the baking sheet on the counter for a few minutes, then transfer the cookies to the cooling rack and let them cool down.