Oatmeal Cream Pie Cookies
Oatmeal Cream Pie Cookies turn simple rolled oats into soft, chewy sandwich cookies with a fluffy marshmallow buttercream center.
This is a from scratch version of the classic lunchbox treat. The cookies bake with crisp edges, soft centers, warm cinnamon, and a sweet filling that tastes light, creamy, and nostalgic.
Why You’ll Love This Recipe
- Soft and chewy texture: Rolled oats give each cookie a tender bite with just enough hearty texture.
- Classic flavor: Brown sugar, cinnamon, and vanilla make the cookies taste warm and cozy.
- Fluffy filling: Marshmallow creme makes the buttercream soft, sweet, and easy to spread.
- Pantry friendly: Most ingredients are simple baking staples you may already have at home.
Fabian’s Budget Tip: Buy rolled oats in a larger container instead of single packets. They cost less per serving and work in cookies, breakfast bowls, meatloaf, and homemade granola. If marshmallow creme costs more in your store, watch for holiday baking sales and grab one extra jar for your pantry.
Ingredients (Serves 4)
For the oatmeal cookies:
- 3/4 cup all purpose flour (95 g)
- 1 cup rolled oats (90 g)
- 1/2 teaspoon baking soda (2 g)
- 1/4 teaspoon salt (1.5 g)
- 3/4 teaspoon ground cinnamon (2 g)
- 1/2 cup unsalted butter, softened (113 g)
- 1/2 cup packed brown sugar (100 g)
- 1/4 cup granulated sugar (50 g)
- 1 large egg (50 g)
- 1 teaspoon vanilla extract (5 ml)
For the marshmallow buttercream filling:
- 1/4 cup unsalted butter, softened (57 g)
- 3/4 cup powdered sugar (90 g)
- 1/2 cup marshmallow creme (45 g)
- 1 tablespoon heavy cream (15 ml), plus 1 teaspoon more if needed
- 1/2 teaspoon vanilla extract (2.5 ml)
- Pinch of salt
Step-by-Step Instructions
1. Heat the Oven and Prep the Pan
Heat the oven to 350°F. Line a baking sheet with parchment paper. Let the butter soften until it gives slightly when pressed, but does not look greasy or melted.
2. Mix the Dry Ingredients
In a medium bowl, stir together the all purpose flour, rolled oats, baking soda, salt, and cinnamon. The mix should smell warm and lightly spiced before it even hits the butter mixture.
3. Cream the Butter and Sugars
Add the softened butter, brown sugar, and granulated sugar to a large bowl. Beat for 2 to 3 minutes, until the mixture looks lighter, creamy, and slightly fluffy. Scrape the bowl so every bit of sugar gets worked into the butter.
4. Add the Egg and Vanilla
Beat in the egg and vanilla until the mixture looks smooth and glossy. At this point, the dough base should smell like caramel, vanilla, and butter.
5. Stir in the Oats and Flour Mixture
Add the dry ingredients to the wet ingredients. Stir just until no dry flour streaks remain. The dough should look thick, soft, and tacky, with oats visible in every scoop. Do not overmix, or the cookies can turn tough.
6. Scoop and Bake
Scoop the dough into 16 even mounds, about 1 tablespoon each. Place them 2 inches apart on the baking sheet. Bake for 8 to 10 minutes, until the edges look set and lightly golden while the centers still look soft and puffed. Your kitchen should smell like toasted oats, cinnamon, and brown sugar.
7. Cool Completely
Let the cookies rest on the hot pan for 5 minutes. Move them to a cooling rack and cool completely. This matters because warm cookies will melt the marshmallow filling.
8. Make the Marshmallow Buttercream
Beat the softened butter until smooth. Add the powdered sugar and beat on low until it starts to blend in, then beat until fluffy. Add the marshmallow creme, heavy cream, vanilla, and salt. Beat until the filling looks pale, smooth, and cloud like. If it feels too thick, add 1 teaspoon of heavy cream.
9. Fill the Cookie Sandwiches
Pair cookies by size. Spread or pipe the filling onto the flat side of half the cookies. Top with the remaining cookies and press gently until the filling reaches the edges. Let them sit for 10 minutes so the filling settles into the cookies.
Expert Troubleshooting & FAQs
Why did my oatmeal cookies spread too much?
The butter may have been too warm, or the dough may have sat in a hot kitchen. Chill the dough for 15 to 20 minutes before baking. Also make sure you measure the flour and oats correctly, since too little dry ingredient makes the dough loose.
Why are my cookies dry instead of chewy?
They likely baked too long. Pull them from the oven when the edges are set but the centers still look soft. The cookies keep cooking on the hot pan as they rest.
Can I use quick oats instead of rolled oats?
Yes, but the texture will be softer and less rustic. Rolled oats give the best chewy bite. Avoid steel cut oats because they stay too firm in this cookie dough.
Can I make the cookies ahead of time?
Yes. Bake the cookies one day ahead and store them in an airtight container. Fill them the day you plan to serve them for the best texture. Once filled, store them covered at room temperature for up to 2 days.
Can I freeze Oatmeal Cream Pie Cookies?
Yes. Freeze the baked, unfilled cookies for up to 2 months. Thaw them at room temperature, then add the fresh marshmallow buttercream filling. You can also freeze filled cookies, but the filling may soften more after thawing.
Estimated Nutritional Facts
These values are rough estimates per serving, based on 2 small sandwich cookies.
- Calories: 820
- Protein: 7 g
- Carbs: 105 g
- Fats: 41 g
Oatmeal Cream Pie Cookies
Ingredients
- 3/4 cup all purpose flour (95 g)
- 1 cup rolled oats (90 g)
- 1/2 teaspoon baking soda (2 g)
- 1/4 teaspoon salt (1.5 g)
- 3/4 teaspoon ground cinnamon (2 g)
- 1/2 cup unsalted butter, softened (113 g)
- 1/2 cup packed brown sugar (100 g)
- 1/4 cup granulated sugar (50 g)
- 1 large egg (50 g)
- 1 teaspoon vanilla extract (5 ml)
- 1/4 cup unsalted butter, softened (57 g)
- 3/4 cup powdered sugar (90 g)
- 1/2 cup marshmallow creme (45 g)
- 1 tablespoon heavy cream (15 ml), plus 1 teaspoon more if needed
- 1/2 teaspoon vanilla extract (2.5 ml)
- Pinch of salt
Instructions
- 1. Heat the Oven and Prep the Pan. Heat the oven to 350°F. Line a baking sheet with parchment paper. Let the butter soften until it gives slightly when pressed, but does not look greasy or melted.
- 2. Mix the Dry Ingredients. In a medium bowl, stir together the all purpose flour, rolled oats, baking soda, salt, and cinnamon. The mix should smell warm and lightly spiced before it even hits the butter mixture.
- 3. Cream the Butter and Sugars. Add the softened butter, brown sugar, and granulated sugar to a large bowl. Beat for 2 to 3 minutes, until the mixture looks lighter, creamy, and slightly fluffy. Scrape the bowl so every bit of sugar gets worked into the butter.
- 4. Add the Egg and Vanilla. Beat in the egg and vanilla until the mixture looks smooth and glossy. At this point, the dough base should smell like caramel, vanilla, and butter.
- 5. Stir in the Oats and Flour Mixture. Add the dry ingredients to the wet ingredients. Stir just until no dry flour streaks remain. The dough should look thick, soft, and tacky, with oats visible in every scoop. Do not overmix, or the cookies can turn tough.
- 6. Scoop and Bake. Scoop the dough into 16 even mounds, about 1 tablespoon each. Place them 2 inches apart on the baking sheet. Bake for 8 to 10 minutes, until the edges look set and lightly golden while the centers still look soft and puffed. Your kitchen should smell like toasted oats, cinnamon, and brown sugar.
- 7. Cool Completely. Let the cookies rest on the hot pan for 5 minutes. Move them to a cooling rack and cool completely. This matters because warm cookies will melt the marshmallow filling.
- 8. Make the Marshmallow Buttercream. Beat the softened butter until smooth. Add the powdered sugar and beat on low until it starts to blend in, then beat until fluffy. Add the marshmallow creme, heavy cream, vanilla, and salt. Beat until the filling looks pale, smooth, and cloud like. If it feels too thick, add 1 teaspoon of heavy cream.
- 9. Fill the Cookie Sandwiches. Pair cookies by size. Spread or pipe the filling onto the flat side of half the cookies. Top with the remaining cookies and press gently until the filling reaches the edges. Let them sit for 10 minutes so the filling settles into the cookies.
