This recipe started as a last-minute holiday rescue in my kitchen the year my oven decided to be dramatic on Christmas Eve. I needed something quick, cheerful, and utterly irresistible to bring to a cookie swap, and this tray of colorful bars fit the bill perfectly. They’re soft and chewy, with the warm caramel notes from packed brown sugar and pockets of candy that deliver a bright, nostalgic crunch. I discovered the balance of texture when I swapped in jimmies for nonpareils — the bars kept their festive look and a satisfying chew that everyone loved.

What makes these bars special is their simplicity: one bowl, pantry-friendly ingredients, and a forgiving bake time that means even beginners can achieve great results. The surface turns golden at the edges while the center stays just set, producing a sliceable bar that finishes cooking as it cools. They’re the sort of thing I make when friends arrive with little notice, when kids want to bake after school, or when I want a holiday plate that looks like I spent hours in the kitchen but didn’t. Every holiday season they reappear in my baking rotation and always disappear first on the cookie table.

Ingredients

• Unsalted butter (1/2 cup / 1 stick): Use room-temperature butter for easier creaming. I favor a high-quality dairy butter such as Plugrá or Kerrygold for richer flavor, but any unsalted stick will work.
• Packed brown sugar (2 cups): Light or dark brown both work; dark will add deeper molasses notes. Pack the sugar firmly into the measuring cup for accurate sweetness and chew.
• Large eggs (2): Bring eggs to room temperature to help them emulsify more smoothly into the batter, resulting in a uniform texture.
• Vanilla extract (1 teaspoon): Pure vanilla adds roundness; avoid imitation if you want a cleaner, more aromatic flavor.
• Salt (1/2 teaspoon): Enhances sweetness and balances the brown sugar — kosher or fine table salt are both fine.
• Baking powder (1 teaspoon): Gives a gentle lift to keep the bars soft rather than dense.
• All-purpose flour (2 cups): Spoon into the measuring cup and level for an accurate amount. Too much flour makes the bars dry, so measure carefully.
• Christmas M&Ms (1 cup): Use seasonal colors or your favorite candy-coated chocolate; reserve a few for the top to keep the surface photogenic.
• Christmas sprinkles / jimmies (1/2 cup): Jimmies maintain color and texture better than nonpareils. Use a mix of red, green, and white for the most festive look.

Instructions

Preheat & Prepare: Preheat the oven to 350°F (177°C). Line a 9×13" metal pan with foil, leaving an overhang to easily lift the bars later, and spray the foil well with cooking spray. Avoid glass pans — a metal pan conducts heat for crisper edges and predictable bake time. Cream Butter and Sugar: In a large bowl, beat 1/2 cup softened unsalted butter and 2 cups packed brown sugar with a stand or hand mixer on medium speed until the mixture is crumbly and slightly glossy, about 1–2 minutes. Scrape the bowl to ensure even mixing. The sugar won’t fluff up like with granulated sugar; you’re aiming for a cohesive, sandy texture. Incorporate Eggs & Flavor: Add 2 large eggs, one at a time, mixing until each is incorporated. Stir in 1 teaspoon vanilla extract. The batter will become glossy and spreadable. If the batter looks separated, a brief additional beat will bring it together. Add Dry Ingredients: Mix in 1/2 teaspoon salt and 1 teaspoon baking powder, followed by 2 cups all-purpose flour. Mix on low until just combined — overmixing develops gluten and will toughen the bars. Finish by folding in 1 cup Christmas M&Ms and 1/2 cup jimmies with a spatula. Spread & Top: Spray your hands lightly with cooking spray (this prevents sticking) and press the wet dough evenly into the prepared pan. Smooth the top with your hands or an offset spatula. Scatter a few reserved candies and sprinkles over the top for decoration. Bake: Bake 22–25 minutes until the edges are golden and the center is just set. Aim for a slightly underbaked center — the bars finish cooking as they cool, and this ensures a soft, chewy texture. Start checking at 20 minutes and rotate the pan halfway through if your oven has hot spots. Cool & Slice: Cool the pan on a wire rack for at least 20 minutes, then use the foil overhang to lift the slab out. Slice into bars with a sharp knife. For clean slices, chill the slab for 15–20 minutes before cutting.

Storage Tips

Store cooled bars in an airtight container at room temperature for up to 4 days. Separate layers with parchment to prevent sticking. For longer storage, freeze individual slices in a single layer on a tray for 1 hour, then transfer to a freezer-safe bag for up to one month. Thaw overnight in the refrigerator or for an hour at room temperature; you can refresh slightly under a warm (not hot) oven for 5 minutes to revive edges.

Ingredient Substitutions

For a dairy-free version, substitute plant-based stick butter in the same amount; the texture will be similar though the flavor will be slightly different. Swap M&Ms for chocolate chips or chopped seasonal chocolate if you prefer fewer candy coatings. To make them gluten-free, use a 1:1 gluten-free flour blend and avoid sprinkles with wheat-based stabilizers. If you want less sweetness, reduce the brown sugar to 1 3/4 cups but expect a slightly less chewy result.

Serving Suggestions

Serve bars warm with a dusting of powdered sugar for a festive look, or arrange on a holiday platter alongside shortbread and peppermint bark for contrast. They pair beautifully with coffee, hot chocolate, or a spiced tea. For a party, stack small squares on a tiered tray and add fresh cranberries and rosemary sprigs for color and aroma.

Cultural Background

Colorful candy-studded bars are a modern American holiday tradition inspired by classic blondies and cookie bars. They combine the chewy structure of a blondie with the playful color of seasonal candies and sprinkles. Variations have been popular for decades at family gatherings and school bake sales, where simple, visually festive treats often become favorites passed down through casual traditions.

Seasonal Adaptations

Adapt the bars for other seasons by swapping candy and sprinkles: pastel candies and light-colored sprinkles for Easter, orange and black for Halloween, or red and pink for Valentine’s Day. For winter, mix in chopped toasted pecans and a sprinkle of sea salt to balance sweetness and add texture.

Meal Prep Tips

Make a double batch and freeze half already sliced for quick hostess gifts or lunchbox treats. Label and date freezer bags, and include a ribbon for gifting. If preparing for a large gathering, bake in two pans to prevent crowding and to get evenly baked slabs with better golden edges.

These bars have been a reliable, joyful addition to my holiday baking for years — quick to make, easy to personalize, and always warmly received. I hope they become a staple in your seasonal baking rotation, too.