Brown Butter Lemon Blueberry Tart

A creamy lemon tart swirled with homemade blueberry jam and nestled in a nutty brown butter Biscoff crust. Bright citrus, sweet blueberries, and warm cookie flavor come together in a dessert that's lighter than cheesecake but every bit as satisfying.

The first thing you'll notice is the crust. Browning the butter transforms crushed Biscoff cookies into something richer and deeper, creating the perfect foundation for a silky lemon filling. A homemade blueberry jam is gently swirled through the custard, giving every slice ribbons of fresh blueberry flavor without overpowering the lemon.

Whether you're serving it at a summer cookout, Easter brunch, Mother's Day, or simply because fresh lemons are on the counter, this tart delivers a beautiful balance of sweet, tart, and buttery flavors.

Yield: 1 (9-inch) tart, 8 servings
Prep Time: 35 minutes
Bake Time: 32 to 34 minutes
Cooling Time: 2 hours (preferably overnight)

Ingredients

Brown Butter Biscoff Crust

113g unsalted butter (1 stick)
75g Biscoff cookie crumbs (about 8 cookies)
75g all-purpose flour (about ½ cup plus 2 tbsp)
50g granulated sugar (¼ cup)
¼ tsp kosher salt
½ tsp vanilla extract

Man-Made Tip: Browning the butter is what makes this crust special. Those rich, nutty flavors pair beautifully with the caramel notes of the Biscoff cookies while balancing the bright lemon filling.

Homemade Blueberry Jam

210g blueberries (1½ cups)
25g granulated sugar (2 tbsp)
10g fresh lemon juice (2 tsp)
4g cornstarch (1 tsp)
Pinch kosher salt

Lemon Filling

396g sweetened condensed milk (1 14-ounce can)
90ml fresh lemon juice (6 tbsp)
Zest of 2 lemons
1 large egg yolk
Pinch kosher salt
1 tsp vanilla extract

Optional Toppings

Fresh blueberries
Lemon slices
Whipped cream
Extra blueberry jam
Crushed Biscoff cookies

Instructions

1. Make the Brown Butter Biscoff Crust

Brown the butter in a small saucepan over medium heat until it smells nutty and the milk solids turn golden brown. Remove from the heat and let cool for about 5 minutes.
Preheat the oven to 350°F (175°C).
In a medium bowl, combine the Biscoff crumbs, flour, sugar, and salt. Stir in the browned butter and vanilla until a thick dough forms.
Press the mixture firmly into the bottom and up the sides of a 9-inch tart pan.
Bake for 15 minutes, until lightly golden. Remove from the oven and lightly dock the bottom with a fork.

2. Prepare the Blueberry Jam

Whisk together the cornstarch and lemon juice until smooth.
In a small saucepan, cook the blueberries and sugar over medium heat for 4 to 5 minutes, gently mashing some of the berries as they soften.
Stir in the cornstarch mixture and salt. Continue cooking for about 2 minutes, until thick and jam-like.
Allow the jam to cool completely before assembling the tart.

3. Make the Lemon Filling

Whisk together the sweetened condensed milk, lemon juice, lemon zest, egg yolk, salt, and vanilla until smooth.

4. Assemble the Tart

Pour the lemon filling into the warm crust.
Dollop the cooled blueberry jam evenly over the filling.
Using a butter knife or skewer, gently swirl the jam through the filling with just a few passes. Avoid over-mixing so the tart keeps its marbled appearance.

5. Bake

Bake at 350°F (175°C) for 17 to 19 minutes, until the edges are set and the center still has a slight wobble.
The filling will continue to set as it cools.

6. Chill

Cool completely at room temperature.
Refrigerate for at least 2 hours, although overnight chilling produces the cleanest slices and best flavor.

Recipe Notes

Browning the butter adds a rich, nutty flavor that takes the Biscoff crust to another level.
Don't over-swirl the blueberry jam or you'll lose the beautiful marbled pattern.
The tart should still have a gentle wobble when it comes out of the oven.
For the cleanest slices and brightest flavor, refrigerate overnight before serving.
Fresh or frozen blueberries both work well for the jam.