When baking cookies, granulated sugar contributes to crispiness and lightness. It also provides a neutral flavor profile so that your cookies can take on the primary flavors in the recipe.

Donna’s Oatmeal Crispies 

Ingredients

• 2 sticks butter
• 1 cup granulated sugar
• 1 cup light brown sugar
• 2 eggs, well beaten
• 1 tsp. vanilla extract
• 1 tsp. cinnamon
• 1 ½ cups sifted flour
• 1 tsp. salt
• 1 tsp. baking soda
• 1 cup raisins
• 3 cups quick oats
• ½ cup chopped nuts

Directions

1. Thoroughly cream shortening and sugars.
2. Add eggs and vanilla.
3. Beat mixture well.
4. Sift dry ingredients and add to creamed mixture.
5. Add oats and nuts. 
6. Drop by teaspoons on engrossed cookie sheet.
7. Bake 10 minutes at 350 degrees.

Source: https://www.westernsugar.com/recipe-center/recipe/dots-oatmeal-crispies/