In a food processor with a steel blade, add the flour, coconut oil, powdered sugar, vanilla, and salt, then process until a crumbly mixture is obtained.
Add the egg and continue to process until the dough lumps are formed.
Transfer the dough to a lightly floured work surface and form a disc shape.
Wrap in plastic wrap and cool in the refrigerator for an hour.
On a floured surface, roll out the dough to a 3-4 mm thick sheet and set aside the baking pan, making sure to create a right angle between the side and the base, ensuring that the edges remain high.
Stab the dough in the tin, evenly, with a fork.
With the remaining dough create the top lid of the pie and place on baking pan lined with baking paper.
Freeze the two dough parts for an hour in the baking pans.
Set the oven to 170°C/ 350°F fan.
Place a sheet of heat resistant nylon or crumpled baking paper on the dough (the crust part not the lid) and fill with dry beans/chickpeas or special weights for baking. (This is known as “Baking blind" and is the process of baking a piecrust or other pastry without the filling.)
Bake the crust blind for 12 minutes.
Remove the weights from the dough and continue baking for 5 more minutes.
In a wide pan place the sugar and caramelize it on high, do not stir it, you can tilt the pan to help but do not use any utensil to try to mix it.
After the sugar turns to caramel with rich amber color add the apples, lemon juice, lemon zest, vanilla extract and coconut oil and stir well.
Cook the filling for 10 minutes until the apples are tender.
Pour the filling to a bowl and add the cornstarch, mix well.
Fill the half-baked crust with the filling, place the frozen lid dough on top.
Brush the lid dough with water and sprinkle sugar on the tart.
Bake for 20 minutes.
Cool the tart at room temperature.
Have a piece and enjoy!