Make the tart crust dough: Mix the flour, salt and sugar in a bowl. Add the fat cut into pieces and, with a fork, cut it into the flour until bits of fat are evenly dispersed in the flour. You should not have pieces of fat any larger than a pea.
Add ice-cold water, 1 tbsp at a time, mixing the dough with the fork, until it comes together.
Shape the dough into a disc and wrap it in plastic wrap or place in an airtight container. Refrigerate for at least 30 minutes.
While the dough chills, make the filling.
Make the filling: Mix all the ingredients in a bowl. Set aside for 15 minutes.
Assemble the tart:On a floured surface, roll out the dough. The disc should be wide enough to at least fit into the bottom and sides of your tart pan. If you'd like a lattice top, make your disc about an inch wider.
Now fold the dough and lift it into a greased tart pan. With your fingers, delicately, push it into the corners of the tart pan.
Run the rolling pin over the top of the tart pan. This will cut out the overhanging pieces of dough. Remove the scraps of dough and push them together into a disc. Refrigerate this ball of scrap dough while you arrange the apples in the tart pan.
Arrange the apples in concentric circles around the tart pan, starting with the outermost layer. You can, of course, use any arrangement you like or even just pile them in haphazardly, but the concentric-circle look is, to my mind, the most beautiful and traditional.
Pour any leftover juices in the bowl on top of the apples.
Now take the remaining dough and roll it wide enough that it would fit over the top of the tart pan. Using a pizza cutter or pastry cutter, cut it into thin strips (you can cut them wide or thin depending on how labor-intensive you want this to be)
Arrange the strips on top of the tart in a lattice pattern. You can find more detailed instructions on making a lattice top in my Maple-Drunk Apple Pie
Sprinkle about 2 tsp of sugar mixed with 1/2 tsp of cinnamon on top of the lattice.
Place the tart in a preheated 375-degree oven for 50 minutes until the juices bubble and top is a nice, light golden-brown.
Allow the tart to stand at least an hour on a rack before you unmold it.