Lemon Curd Mascarpone Tart

To Make the Pate Sucree (Sweet Shortcrust Pastry)

1. Cream the butter and sugar on low in a stand mixer fitted with a paddle attachment.
2. Add the egg and mix. It will look curdled, but that is okay.
3. Add all dry ingredients and mix just until combined. Remove the dough from the mixer and shape into a flat round disk. Wrap with plastic and refrigerate for at least 30 minutes.
4. If the dough chills for more than an hour, let the dough sit out for 20-30 minutes so that it is easier to work with. The dough gets really firm when it chills for a long time.
5. Preheat oven to 325 degrees and begin making the tart.
6. On a lightly floured work surface, roll the dough out into a circle that is 1/8 inch thick.
7. Place a 9 inch tart pan upside down on the dough and cut out a circle that is 2 inches bigger than the tart pan.
8. Next, press the dough into the tart pans and remove the excess dough along the edges with the palm of your hand or with a knife.
9. Prick the tarts with a fork so no air pockets form, and place in the freezer for 1 hour.
10. Line with parchment and pie weights (or rice) so that the tart keep its shape while baking.
11. Bake for 20-25 minutes. Remove the pie weights and liner for the last 5 minutes of baking. The tart is done when the edges are lightly golden.
12. Allow the tart to cool completely before filling.

To Make the Lemon Curd

1. Combine the sugar and cornstarch in a medium glass or metal bowl and whisk. Add the egg yolk, whole eggs, fresh lemon juice, and granulated sugar. Whisk to combine.
2. Next, fill a medium pot with 1-2 inches of water, and place the bowl over the water, making sure that the bottom of the bowl doesn’t actually touch the water.
3. Turn the stove onto medium high heat to get the water to a simmer quickly, and then turn the heat down so it stays at a simmer. While the water is coming to a simmer, begin stirring the lemon mixture so that it doesn’t scramble.
4. Whisk the lemon curd until it is pale and thickens. This takes 5 – 10 minutes. 
5. Remove the bowl from the heat and whisk in the pats of butter one at a time until they are melted and combined with the curd. Whisk the curd for 1-2 minutes after removing from the heat to get the right consistency.
6. Place a piece of plastic directly on top of the curd so that the plastic is touching it. Cover the bowl with another layer of plastic wrap to make sure it’s sealed well, and refrigerate for 20 minutes.

For the Lemon Mascarpone Filling

1. Whip the heavy cream and powdered sugar with a hand mixer until stiff peaks form.
2. In a separate bowl, cream the mascarpone cheese, lemon zest, and salt. Add to the heavy cream and whip until smooth and creamy.
3. Pour about 2/3 of the lemon mascarpone filling into the cooled tart shell (or as much as will fit), leaving a little gap at the top for the lemon curd. Smooth the filling with an offset spatula until completely even.
4. Next, pour the lemon curd on top and smooth with the offset spatula. You may not need all of the curd, but most of it should fit on top.
5. Refrigerate for 30 minutes. Meanwhile, fill a piping bag fitted with a French star tip with the remaining mascarpone. Pipe a border around the edge if the tart if desired. For additional texture, add crushed almonds along the border (completely optional). 
6. Refrigerate until ready to serve. Store covered in the fridge for up to a week.