Key Lime Bars

Key Lime Bars are citrusy and smooth with a cinnamon-spiced crust. The sour cream topping adds the perfect creaminess in every bite. There is no need for other toppings! Great for parties or days when you are having a citrus craving.

When I worked as a Pastry Chef, I made these bars at least twice a week. They were such a  huge hit at the restaurant I worked at that I had endless requests for them. Key Lime Bars are delicious served in large squares or small cubes on party trays. I would serve small squares of them with chocolate brownies and my Louise’s Lemon Brownies. They have a Key Lime cheesecake type texture and the cinnamon in the crust is the perfect complement to the lime taste. 

WHAT IS A KEY LIME?

Key limes are small, spherical citrus fruit that are about 1-2 inches across, the size of a ping-pong ball. They are thin-skinned, often containing a few seeds and a yellow-green inside. Key limes are tartar than other limes, such as Persian limes, which make their juice a perfect balance for sweet desserts. They only contain about 2-3 teaspoons of juice per Key lime. Also known as the “Mexican lime” and “West Indies lime”, they were cultivated for thousands of years in the Indo-Malayan region. Key limes are less common in the United States but used more throughout the world. In the US they are grown in the Florida Keys, California, and Texas. 

A BRIEF HISTORY OF THE KEY LIME

Some believe that in 1493 that Columbus brought Key lime seeds to the Caribbean from Asia. By the late 1830s, Key lime trees were growing in the Florida Keys. Before the Overseas Highway through the Florida Keys was built in 1930, locals used sweetened condensed milk because of the lack of fresh milk. Locals would add Key lime juice to cut the sweetness of the condensed milk. In 1926 a hurricane in the Florida keys wiped out most of the Key lime plantations. Because Key limes are widely used in Hispanic and Asian cuisines, the Key lime has made a come back due to the demand over the years.

*Read more about Key Limes vs Persian Limes in my Blog post. 

INGREDIENTS TO MAKE KEY LIME BARS

• Graham crackers
• Cinnamon 
• Unsalted butter
• Eggs
• Sweetened condensed milk
• Key limes
• Sour cream 
• Sugar 
• Pure vanilla extract

HOW TO MAKE KEY LIME BARS

• Preheat oven to 325°F.
• Spray a 13 x 9-inch pan spray with cooking spray, and line with parchment paper letting it hang over by 2-inches over the pan. 
• In a food processor, process the graham crackers and cinnamon until finely ground.
• Pour into a medium-sized bowl and add the melted butter.
• Press into prepared pan and bake for 8 minutes.
• In a large bowl, whisk the egg and egg yolks; add the sweetened condensed milk and mix until incorporated.
• Add the zest of 1 lime and lime juice and whisk until the mixture is smooth.
• Pour filling into baked crust; bake for 25 minutes or until firm.
• Meanwhile, in a separate small bowl stir together the sour cream, sugar, and vanilla.
• After removing the pan from the oven, spread the sour cream mixture evenly over the filling.
• Bake for 10-15 minutes more.
• Cool, sprinkle with reserved lime zest, and refrigerate before cutting.

OTHER DELICIOUS RECIPES TO TRY:

• Lemon Bars
• Louise’s Lemon Brownies
• The BEST Brownies
• Easy Brownies
• Kisses Peanut Butter Blossoms
• Coconut Macaroons

Print Recipe

Key Lime Bars

Key Lime Bars are citrusy and smooth with a cinnamon spiced crust. The sour cream topping adds the perfect creaminess in every bite. No need for other toppings! Great for parties or days when you are having a citrus craving. 

Prep Time15 minutes mins

Cook Time25 minutes mins

Cooling Time:10 minutes mins

Total Time50 minutes mins

Course: Dessert

Cuisine: American

Keyword: bars, graham crackers, key lime

Servings: 12 servings

Author: Louise Rio

Ingredients

Crust (13 x 9x 2-inch pan):

• 2 cups graham cracker crumbs, about 13 graham crackers
• ¾ tsp ground cinnamon
• 7 Tbsp unsalted butter, melted

Key Lime Filling:

• 1 large egg plus 3 egg yolks
• 2 (14 ounce) cans sweetened condensed milk
• Zest of 2 limes, one for filling and reserve one for topping
• ¾ cup plus 2 Tbsp Key lime or Persian lime juice

Sour Cream Topping:

• 1 ½ cups sour cream
• 2 Tbsp sugar
• 1 tsp pure vanilla extract

Instructions

• Preheat oven to 325°F. Spray a 13 x 9-inch pan spray with cooking spray, and line with parchment paper letting it hang over by 2-inches over the pan. In a food processor, process the graham crackers and cinnamon until finely ground. Pour into a medium-sized bowl and add the melted butter. Press into prepared pan and bake for 8 minutes.
• In a large bowl, whisk the egg and egg yolks; add the sweetened condensed milk and mix until incorporated. Add zest of 1 lime and lime juice and whisk until mixture is smooth. Pour filling into baked crust; bake for 25 minutes or until firm.
• Meanwhile, in a separate small bowl stir together the sour cream, sugar and vanilla. After removing the pan from the oven, spread the sour cream mixture evenly over the filling. Bake for 10-15 minutes more. Cool, sprinkle with reserved lime zest, and refrigerate before cutting.

Notes

• These can be made on a 13 x 9-inch baking pan or sheet tray.
• To get clean-cut squares, refrigerate first for at least 1 hour. After each cut wipe the knife off with a paper towel. 
• For the crust, optional: can use Biscoff (Belgian speculaas) cookies instead of graham crackers and cinnamon.