This version of sugar cookie bars has been a holiday constant at my house for as long as I can remember. I first discovered the formula one December while trying to simplify a time-consuming cookie recipe into something that could be baked in one pan and still keep that tender, cut-cookie texture. The result was a tray of buttery bars with just the right chew, a delicate crumb from cornstarch, and a surface that takes frosting beautifully. It quickly became my go-to when I needed something festive but forgiving.

The bars are soft in the center with lightly golden edges and a cookie flavor that is amplified by a hint of almond and pure vanilla. When whisper-thin frosting is spread across the cooled slab and studded with red, green, and white nonpareil sprinkles, the result is undeniably joyful. I love these for cookie exchanges, as a make-ahead gift, or just set out on a tray when family visits—people always come back for another piece.

Ingredients

• All-purpose flour: 2 cups. Use a reliable brand like King Arthur or Gold Medal. Spoon and level for accuracy. Flour gives structure; we balance it with cornstarch for tenderness.
• Cornstarch: 2 teaspoons. A small amount softens the crumb and creates that slightly cake-like, melt-in-your-mouth texture reminiscent of classic cut sugar cookies.
• Baking powder: 1 teaspoon. Provides a gentle lift so the bars remain tender and not dense.
• Salted sweet cream butter: 3/4 cup for the base and 1 cup for the frosting, both softened. Use cultured butter like Plugra or a trusted supermarket brand; it adds depth and spreadability.
• Granulated sugar: 1 cup. Provides structure and chew; for a crisper edge you can substitute half with superfine sugar but standard granulated is fine.
• Vanilla extract: 1 tablespoon pure vanilla. Clear vanilla can be used in frosting for a bright finish.
• Almond extract: 1 teaspoon. A little goes a long way; it brightens the cookie flavor and pairs beautifully with vanilla.
• Eggs: 2 large, room temperature. Eggs help bind and provide moisture; let them sit at room temperature for 20 to 30 minutes for even incorporation.
• Christmas nonpareil sprinkles: 4 tablespoons red, green, and white. Use smaller nonpareils so they distribute evenly through the batter and on top of the frosting.
• Powdered sugar: 2 1/2 cups for the buttercream. Sift if lumpy for a silky frosting.
• Heavy cream: 4 to 5 tablespoons to adjust frosting consistency to spreadable but not runny.

Instructions

Prep the pan: Preheat the oven to 350 degrees F. Line a 9 by 9 inch baking dish with a parchment paper sling and spray lightly with baking spray such as Baker's Joy. The sling makes removing the slab easy and keeps edges clean. Combine dry ingredients: In a small bowl whisk together 2 cups all-purpose flour, 2 teaspoons cornstarch, and 1 teaspoon baking powder. Whisking distributes the leavener and cornstarch evenly so you do not get streaks of powder in the finished bar. Cream the butter and sugar: Using a medium bowl and a handheld mixer on high, beat 3/4 cup softened butter for 1 minute until smooth. Add 1 cup granulated sugar, 1 tablespoon vanilla extract, and 1 teaspoon almond extract, beating for 1 to 1 1/2 minutes until light and fluffy. The creaming step incorporates air which gives a lighter final texture. Add eggs: Reduce the mixer to low and add the eggs one at a time, beating well after each. Room temperature eggs emulsify more easily; if batter looks broken, beat on medium-low until smooth before adding flour. Mix in dry ingredients: Increase speed to medium-low and add the flour mixture one cup at a time, mixing just until incorporated. Overmixing develops gluten and will toughen the bars; stop when you see uniform streaks disappear. Fold in sprinkles and bake: Gently fold in 4 tablespoons Christmas nonpareil sprinkles until combined. Spread dough evenly into the prepared pan using an offset or silicone spatula. Bake 20 to 22 minutes until the top is just turning golden and a toothpick comes out clean. Allow to cool completely in the pan. Make the buttercream: In a medium bowl, beat 1 cup softened butter with 1 teaspoon clear vanilla and 1/2 teaspoon almond extract for 1 minute at medium-high. Reduce speed to low and add 2 1/2 cups powdered sugar in 1/2 cup increments, alternating with 4 to 5 tablespoons heavy cream. Finish beating on medium-high 1 to 1 1/2 minutes until silky. Frost and finish: Once bars are fully cooled, lift with the parchment sling and place on a cooling rack. Use an offset spatula to spread buttercream evenly across the slab. Sprinkle an even layer of nonpareils on top. Slice into 1 1/2 by 3 inch bars and enjoy.

Storage Tips

Store frosted bars in an airtight container at room temperature for up to 3 days. If your home is warm, refrigerate the container; bring bars back to room temperature for 20 to 30 minutes before serving so the buttercream softens. For longer storage, freeze unfrosted bars in a single layer on a sheet pan until firm, then stack with parchment between layers in an airtight container for up to 3 months. Thaw overnight in the refrigerator and frost the next day for best texture.

Ingredient Substitutions

For a dairy-free version substitute dairy-free margarine and a non-dairy creamer in place of heavy cream and use a vegan buttercream recipe; note texture will differ slightly. To make gluten-free bars, use a 1-to-1 gluten-free flour blend and add 1/4 teaspoon xanthan gum if your blend lacks it. If you prefer no almond flavor, omit almond extract and increase vanilla to 1 1/2 tablespoons. You can swap nonpareil sprinkles for jimmies or chopped festive candies but the small nonpareils give the nicest distribution in the batter.

Serving Suggestions

Serve bars on a festive platter with fresh cranberries or rosemary sprigs for color contrast. They pair wonderfully with hot chocolate, eggnog, or a cup of strong coffee. For a party, cut into smaller 1 by 2 inch bites and place on a tiered tray with other small cookies. For gifting, wrap two or three in waxed paper and tie with ribbon; they make charming homemade gifts for neighbors and teachers.

Cultural Background

These bars are an American holiday adaptation that borrows elements from classic rolled sugar cookies and sheet cake techniques. One-pan versions of cut cookies became popular for their ease and speed while preserving the nostalgic flavors families associate with seasonal celebrations. Sprinkles became a modern holiday staple in the mid 20th century as confectionery decoration became more accessible, adding a cheerful aesthetic that signals holiday baking across many households.

Seasonal Adaptations

For winter variations, stir in a teaspoon of orange zest and swap almond extract for orange extract for a citrus twist. At Valentine’s Day use pink and white sprinkles, and at St. Patrick’s Day switch to green and white sprinkles. For a spiced holiday version add 1/2 teaspoon ground ginger and 1/4 teaspoon cinnamon to the dry mix. These simple swaps keep the method unchanged but adapt the flavor for any season.

Meal Prep Tips

Bake the slab two days ahead, cool, and wrap tightly unfrosted. Make the buttercream the morning you plan to serve and assemble in minutes. If you plan to transport, frost at the venue or keep the frosted slab chilled to prevent smudging. Cutting with a warm, clean knife produces the neatest slices; wipe the knife between cuts for smooth edges. For portion control freeze a fully frosted slab briefly to set the frosting, then slice and rewrap individual bars for grab-and-go breakfasts or school snacks.

These sugar cookie bars are simple, crowd-pleasing, and full of holiday nostalgia. They are one of those recipes that makes the season feel a little warmer, and I hope they become a tradition in your home as they are in mine. Happy baking and may your kitchen be full of laughter and the smell of butter and vanilla.