In a food processor, add the flour, powdered sugar, and salt, and mix until combined.
Add the cold cubed butter, and blend until the mixture is crumbly and has a sand texture.
If you don't have a food processor, you can do it by hand, mixing the cold butter into the flour mixture. Make sure that your hands are cold.
Then, add the egg, and mix until a dough forms. Try not to overmix the dough.
Cover the dough with plastic wrap, flatten it out using your hands so it will be easier to roll out, and let it chill in the fridge for at least an hour.
Transfer the dough onto a clean floured surface, roll it with a rolling pin into a circle, moving the dough constantly to ensure it doesn’t stick to the surface, and transfer it into a 9-inch tart pan.
Cut off the extra edges. Make little holes with a fork and freeze for 20 minutes.
Bake in a 180°C (350°F) preheated oven for about 15-20 minutes or until the crust is a light golden brown color. Remove from the oven and allow it to cool for about 10 minutes.
Make the almond filling (frangipane): into a large mixing bowl, add the room temperature butter, salt, and sugar, and mix with an electric hand mixer until creamy and smooth.
Add the eggs and mix until well combined.
Add the almond flour and flour and mix until the mixture is smooth and homogeneous. Transfer the almond cream to a piping bag and cut a small but not too small slit in the tip.
Assemble the tart
Pipe the filling into the cooled tart crust in a spiral or zigzag pattern, then smooth the top gently with an offset spatula. Sprinkle sliced almonds evenly over the top.
Bake at 175°C (350°F) for 30–35 minutes, or until the filling is puffed, golden, and set in the center. If the almonds brown too quickly, cover loosely with foil during the last 10 minutes.
Let the tart cool completely in the pan. Dust with powdered sugar before serving if desired.
Notes
Use COLD butterfor the crust, I suggest cutting the butter into cubes and then placing it in the fridge, so when you are ready to use it, it will be very cold.
Freeze the crust for at least 20 minutes before baking it. This will keep your crust from collapsing while baking.
Let the pastry dough rest in the fridge for at least 30 minutes before handling it. This will make it easier to roll out the crust and handle it.
Cream the frangipane just until smooth. Overmixing adds too much air and may cause the filling to puff unevenly or collapse.
If the crust puffs a bit while baking, press it down using a cup.
Don’t overfill the tart. Leave a little space at the top of the crust—the filling will rise slightly as it bakes.
Use an easy-release tart pan. I use an easy-release tart pan for all of our tart recipes. This makes sure that your tart will be easy to release from the pan.
Cool the tart fully before slicing. This helps the filling set properly and gives clean, bakery-style slices.
. This helps the filling set properly and gives clean, bakery-style slices.