Oatmeal Creme Pie Bars
Soft and chewy oatmeal creme pie bars with a tender cinnamon oatmeal cookie base and a fluffy marshmallow creme filling. All the nostalgia of the classic snack cake in easy, sliceable bar form.
Servings: 16 bars
Calories: 399kcal
Equipment
- 1 baking pan 8x8, 9x9, or 9x13
- Parchment paper
- large mixing bowls
- Whisk
- Electric mixer
- Spatula
Ingredients
Oatmeal Cookie Bars
- 1 cup butter melted and cooled
- 1 ½ cups light brown sugar
- 2 large eggs
- 1 tablespoon vanilla extract
- 1 ¾ cups all-purpose flour
- 1 teaspoon baking soda
- ½ teaspoon baking powder
- 1 teaspoon cinnamon
- ½ teaspoon nutmeg optional
- ½ teaspoon salt
- 2 cups old-fashioned oats or quick oats
Marshmallow Creme Filling
- ½ cup butter softened
- 1 ½ cups powdered sugar
- 1 cup marshmallow fluff
- 1 teaspoon vanilla extract
- salt Pinch of salt
Instructions
Make the Oatmeal Cookie Bars
- Preheat the oven to 350°F. For ultra-thick bars, line an 8x8 or 9x9 pan with parchment paper. For thinner bars, use a 9x13 pan.
- In a large bowl, whisk 1 cup melted butter and 1 1/2 cups brown sugar until glossy.
- Whisk in 2 eggs and 1 tablespoon vanilla.
- Add 1 3/4 cups flour, 1 teaspoon baking soda, 1/2 teaspoon baking powder, 1 teaspoon cinnamon, 1/2 teaspoon nutmeg, and 1/2 teaspoon salt. Mix until just combined, then fold in 2 cups oats.
- Spread the dough evenly into the prepared pan.
- Bake until set: 26 to 32 minutes for an 8x8 pan, 22 to 27 minutes for a 9x9 pan, or 18 to 23 minutes for a 9x13 pan.
- Let the bars cool completely in the pan.
Make the Marshmallow Creme Filling
- Beat 1/2 cup softened butter, 1 1/2 cups powdered sugar, 1 cup marshmallow fluff, 1 teaspoon vanilla, and a pinch of salt until light and fluffy.
- Spread the filling over the cooled cookie layer.
- Chill for 20 to 30 minutes before slicing for clean cuts.
Notes
Oats: Old-fashioned oats give chewier, denser bars. Quick oats bake up softer and more cake-like.
Fluffier filling: Beat in 1 to 2 tablespoons of milk to lighten the marshmallow filling.
Clean slices: The bars cut neatest when chilled.
Extra nostalgia: Dust the top with cinnamon sugar before serving.
Storage: Refrigerate in an airtight container for 5 to 6 days, or freeze for up to 2 months.
Nutrition values are estimates based on 16 bars.
Nutrition
Calories: 399kcal | Carbohydrates: 56g | Protein: 3g | Fat: 19g | Saturated Fat: 11g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 5g | Trans Fat: 1g | Cholesterol: 70mg | Sodium: 286mg | Potassium: 102mg | Fiber: 1g | Sugar: 36g | Vitamin A: 565IU | Vitamin C: 0.01mg | Calcium: 40mg | Iron: 1mg