Preheat your oven to 350°F and line your large baking sheets with parchment paper for a non-stick surface. This ensures your chewy oatmeal cookies lift off easily without breaking their delicate and soft edges today.

In a large mixing bowl, beat the softened butter, dark brown sugar, and white sugar until very light. Mixing for three minutes creates a fluffy base that makes the cookies soft instead of hard and crunchy.

Add the eggs one at a time and beat well after each addition to keep the dough smooth. Stir in the vanilla extract to add that classic sweet aroma that defines every good homemade farmhouse cookie.

In a separate medium bowl, whisk the flour, baking soda, ground cinnamon, and salt together until well combined. The cinnamon is very important because it gives the oatmeal cookies their signature warm and spicy flavor.

Gradually add the flour mixture into the butter mixture while keeping your mixer on a very low speed. Mix just until the white flour disappears so you do not overwork the dough and make it tough.

Add the quick-cooking oats and fold them in gently using a large rubber spatula or a wooden spoon. Ensure the oats are spread evenly so every single bite has that perfect chewy and rustic texture today.

Use a cookie scoop to place rounded tablespoons of dough onto the sheets, leaving two inches of space. Bake for ten to twelve minutes until the edges are golden but the centers still look soft.

Let the cookies sit on the hot baking sheet for five minutes to firm up their soft structure. Move them to a wire rack and let them cool completely before you try to add the filling.

Beat the butter, powdered sugar, marshmallow fluff, and heavy cream together until the frosting is very white and fluffy. This marshmallow center is what makes the Joanna Gaines version taste like a professional bakery treat.

Spread a thick layer of cream on the flat side of one cookie and top with another. Press down gently so the cream reaches the edges and creates a beautiful, thick, and very tempting sandwich.