This tart combines a silky blueberry buttermilk filling with a sharp, buttery shortbread crust and is topped with a warm cinnamon almond crumble. The crumble is your favorite part of a blueberry muffin baked off just by itself and sprinkled on top of the creamy tart after baking.

I did some experimenting with the crumble topping. First, I added it to the tart half way through baking but the crumb still sunk to the bottom of the tart and didn't add the texture that I was looking for. Baking it off separately allowed for a crunchy texture that balanced out the creaminess of the filling.

Blueberry Buttermilk Tart

Lemon Shortbread Crust

1/2 cup unsalted butter, softened
1/2 cup powdered sugar
1 egg yolk
1 tablespoon lemon zest
1 1/2 cup flour
pinch of salt

Blueberry Buttermilk Filling

2 eggs
4 tablespoons unsalted butter, softened
3/4 cup sugar
1 1/2 tablespoon flour
pinch of salt
1/2 cup buttermilk
1 tablespoon lemon juice
1 teaspoon vanilla bean paste
1 teaspoon lemon zest
1/2 cup fresh blueberries

Cinnamon Almond Crumb

1/4 cup brown sugar
1/2 cup flour
pinch of salt
4 tablespoon unsalted butter, softened
1 teaspoon cinnamon
1/4 cup sliced almonds

lemon shortbread crust:

Preheat the oven to 450 degrees f.

Cream together the butter and confectioners sugar for a full minute until it has lightened in color and is fluffy. Then add the egg yolk, salt, and lemon zest and mix until it comes together. Add the flour in to the mixture gradually and mix until it forms a dough. It will start out dry and crumbly but keep going and it will all come together. Once the dough comes together, let rest for 5 minutes to firm up.

Then, roll the dough gently on a floured surface into roughly an 10 inch circle. Place the dough in a 9 inch tart pan and use your fingers to press the dough into the bottom and side. Pinch together any cracks. Use the side of a measuring cup to press the dough into the sides and cut off any excess from the top of the pan.

Generously dock the bottom and sides of the dough and par bake for 8-10 minutes until it begins to brown.

Remove the crust, let cool while you prepare the filling and lower the oven temperature to 350 degree F.

Blueberry buttermilk filling:

Whisk together eggs until frothy. Then add butter, sugar, pinch of salt and flour and mix. Make sure you are using softened butter (like sitting on the counter over night softened butter). Add in buttermilk, lemon juice, zest, and vanilla and mix until everything comes together. If you still have some small lumps of butter that is okay. Pour the mixture into the cooled crust and top with a scattering of fresh blueberries.

Place the tart in the oven for 35-40 minutes until set.

Cinnamon almond crumble topping:

Mix together the softened butter, brown sugar, flour, cinnamon, and salt together with your hands until it forms the texture of wet sand and forms crumbs. Mix in the almonds and place on a cookie sheet lining with a silicon mat or parchment paper.

When there is 20 minutes left on the tart, add the crumble topping to the oven and bake until it begins to brown