• Preheat your oven to 350°F.

Prepare the Cookie Dough

• Add the softened butter, brown sugar and white granulated sugar to a large mixing bowl.
• Use an electric hand mixer to cream the ingredients together on high speed for about 2 minutes or until the sugar is dissolved.
• Add in the eggs and beat again until they’re fully combined.
• Reduce the speed of your hand mixer.
• Gently whisk in the old fashioned oats, quick oats, flour, baking soda, and baking powder.

Bake the Cookies

• Use a standard size cookie scoop or large spoon to drop balls of cookie dough onto a greased or parchment paper lined baking sheet.
• Flatten the top of each ball slightly to help the cookies spread out.
• Bake for 11 minutes, then let them cool for 20 minutes on a wire rack.

Prepare the Cream Filling

• While your cookies are baking, beat the butter and powdered sugar together until smooth and creamy.

Fill the Cookies

• Use a piping bag or spatula to sandwich a generous amount of cream filling between two cooled cookies.
• Repeat the process with your remaining cookies and cream filling.