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BEST Key Lime Pie Bars

Best key lime pie bars with a warm spiced Biscoff cookie crust and neon lime custard baked until just set. Topped with coconut whipped cream and toasted coconut flakes for a creamy, layered finish.
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Prep Time 30 minutes
Cook Time 23 minutes
Chill 2 hours
Total Time 2 hours 53 minutes
Course: Dessert
Cuisine: American
Calories: 340
Ingredients Equipment Method Notes

Ingredients
  

Biscoff crust
  • 1.5 cup Biscoff cookie crumbs Warm spiced cookie crumbs for the crust.
  • 5 tbsp melted butter Melted and cooled slightly so it blends smoothly.
Lime custard
  • 3 egg yolks Use yolks only for a rich, custardy set.
  • 2 tsp key lime zest Zest adds perfume and a bright lime aroma.
  • 0.5 cup key lime juice Strained juice helps keep the custard texture smooth.
  • 1 can (14 oz) sweetened condensed milk Sweetens and thickens as it bakes.
Coconut topping
  • 1 cup heavy cream Cold cream whips more easily for a fluffy topping.
  • 2 tbsp powdered sugar Adds sweetness and stabilizes the whipped cream.
  • 0.5 tsp coconut extract Boosts coconut flavor in the whipped topping.
  • 1 toasted coconut flakes Sprinkle on right before serving for the best crunch.

Equipment

  • 1 sheet pan
  • 1 8x8 baking pan

Method
 

Bake the crust
  1. Preheat the oven to 350°F and line an 8x8 pan for easy removal.
  2. Mix Biscoff cookie crumbs and melted butter, then press firmly into the pan in an even layer.
  3. Bake the crust for 8 minutes, then remove and keep the oven on.
Make the lime custard
  1. Beat the egg yolks with the key lime zest until smooth and slightly lighter in color.
  2. Mix in the sweetened condensed milk, then add the key lime juice and stir until fully combined.
  3. Pour the lime custard over the hot crust, then bake for 15 minutes until just set in the center.
Chill and top
  1. Chill the bars for 2+ hours until cold and firm enough to slice.
  2. Whip the heavy cream with powdered sugar and coconut extract to soft peaks, then spread over the chilled bars.
  3. Top with toasted coconut flakes and cut into bars to serve.

Notes

Pro tip: toast the coconut flakes in a dry pan just until golden, then cool completely before topping so they stay crisp. Store covered in the refrigerator up to 3 days; freezing isn’t recommended for the whipped topping. For a dairy-light swap, use a coconut-based cream substitute that whips well in place of heavy cream.