Place flour, sugar, ground almonds and butter in the food processor and pulse until crumbly. Add egg and mix until the dough comes together. Add a little water if needed. Form dough into ball and wrap in plastic. Let rest for 1 hour.
Preheat oven to 350 degrees. On a lightly floured surface roll the pastry out and fit it into the bottom and sides of fluted 9 inch tart pan. Prick the bottom with a fork in several places and then bake for 12 to 15 minutes.
For the filling, in a small sauce pan whisk together lemon juice, sugar, eggs and yolks, cornstarch and sea salt over a medium heat until boiling and thickened, 2 to 5 minutes. Make sure the mixture comes to a boil or the cornstarch won't activate. Once it boils do not cook it longer than 1 minute. Remove from heat and strain into a bowl. Whisk in olive oil and lemon zest.
When the crust is ready, take it out of the oven and carefully pour the lemon curd onto the shortbread base and return the pan to the oven. Bake until topping is set 10 to 15 minutes more. Allow to cool to room temperature then refrigerate until cold before cutting it. Sprinkle with powdered sugar right before serving.