Old-Fashioned Frosted Oatmeal Raisin Bars Recipe

 

These Old-Fashioned Frosted Oatmeal Raisin Bars combine everything you love about classic oatmeal raisin cookies in an easy-to-slice dessert bar. Made with hearty rolled oats, warm cinnamon, sweet raisins, and a rich brown butter frosting, they’re soft, chewy, and perfect for holidays, potlucks, bake sales, or an afternoon treat with coffee.

Bake soft and chewy Old-Fashioned Frosted Oatmeal Raisin Bars topped with rich brown butter frosting. An easy homemade dessert that’s perfect for sharing.

Recipe Details

• Prep Time: 20 minutes
• Cook Time: 30 minutes
• Cooling Time: 45 minutes
• Total Time: 1 hour 35 minutes
• Servings: 16 bars

Ingredients

Oatmeal Raisin Bars

• 1 cup unsalted butter, softened
• 1 cup packed light brown sugar
• ½ cup granulated sugar
• 2 large eggs
• 1 tablespoon vanilla extract
• 2 cups all-purpose flour
• 2 cups old-fashioned rolled oats
• 2 teaspoons ground cinnamon
• ½ teaspoon ground nutmeg
• ¼ teaspoon ground cloves
• 1 teaspoon baking soda
• ½ teaspoon salt
• 1½ cups raisins
• ½ cup chopped walnuts (optional)

Brown Butter Frosting

• ½ cup unsalted butter
• 3 cups powdered sugar, sifted
• 2–4 tablespoons milk or heavy cream
• 1 teaspoon vanilla extract

Instructions

1. Prepare the Pan

Preheat your oven to 350°F (175°C).

Grease a 9×13-inch baking pan or line it with parchment paper for easy removal.

For softer raisins, soak them in hot water for about 10 minutes, then drain and pat dry.

2. Cream the Butter and Sugars

Beat the softened butter, brown sugar, and granulated sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition.

Stir in the vanilla extract.

3. Combine the Dry Ingredients

In another bowl, whisk together the flour, oats, cinnamon, nutmeg, cloves, baking soda, and salt.

Gradually add the dry ingredients to the butter mixture until just combined.

Fold in the raisins and chopped walnuts.

4. Bake

Spread the batter evenly into the prepared pan.

Bake for 25–30 minutes, or until the edges are lightly golden and a toothpick inserted into the center comes out clean.

Allow the bars to cool completely before frosting.

5. Make the Brown Butter Frosting

Melt the butter in a saucepan over medium heat.

Continue cooking, stirring frequently, until it turns golden brown and develops a rich, nutty aroma.

Remove from the heat and let cool slightly.

Whisk in the powdered sugar, vanilla, and enough milk to create a smooth, spreadable frosting.

6. Frost and Slice

Spread the frosting evenly over the cooled bars.

Create decorative swirls using the back of a spoon or an offset spatula.

For clean slices, refrigerate the frosted bars for 30 minutes before cutting into squares.

Serving Suggestions

These oatmeal bars are delicious served with:

• A cold glass of milk
• Freshly brewed coffee
• Hot tea
• Vanilla ice cream
• Fresh berries for a lighter dessert

Storage

Room Temperature

Store in an airtight container for up to 3 days.

Refrigerator

Keep refrigerated for up to 1 week.

Freezer

Freeze unfrosted bars for up to 3 months.

If freezing frosted bars, freeze them in a single layer first before transferring them to a storage container.

Frequently Asked Questions

Can I use quick oats?

Yes, but old-fashioned rolled oats provide a chewier texture and more traditional oatmeal flavor.

Why is my frosting grainy?

Be sure to sift the powdered sugar and avoid letting the browned butter cool too much before mixing. Whisk thoroughly until smooth.

Can I replace the raisins?

Absolutely. Dried cranberries, chopped dried cherries, or chocolate chips all make delicious substitutions.

Can I prepare these ahead of time?

Yes. These bars actually taste even better the next day as the flavors continue to develop.

Tips for the Best Oatmeal Raisin Bars

• Soak the raisins before mixing them into the batter for extra softness.
• Don’t overmix the batter after adding the flour.
• Allow the bars to cool completely before frosting.
• Brown the butter carefully for maximum flavor without burning it.
• Chill before slicing for bakery-style squares.

Final Thoughts

Old-Fashioned Frosted Oatmeal Raisin Bars are the perfect combination of soft cookie bars and rich frosted dessert squares. Packed with warm spices, chewy oats, sweet raisins, and topped with buttery frosting, they’re ideal for sharing with family and friends. Whether you’re baking for a holiday gathering or simply craving a nostalgic homemade treat, this recipe is sure to become a favorite.

Make a batch ahead of time, slice into squares, and enjoy a classic dessert that’s perfect for every occasion.

Category: Bars & Brownies