For the filling:
7 medium-sized (6oz) apples, peeled, cored and quartered lengthwise
1/2 lemon
1/4 cup sugar
2 tablespoons water
2 tablespoons butter, melted
1/4 cup warm apricot glaze
1 10 or 11-inch prepared tart shell*, refrigerated
For the apricot glaze:
1/2 cup apricot preserves
2 tablespoons water or orange-flavored liqueur such as Cointreau or Triple Sec
Squirt the apple quarters with lemon and set aside.
Cut 4 apples worth of quarters (16 pieces), into chunks and place in a medium saucepan with sugar and 1/4 cup water. Cook over medium heat with cover slightly akimbo for about 3 minutes until cubes are giving off a nice appley scent. Remove the cover and cook a few minutes longer, stirring, until apples have broken down into a compote. Set aside to cool.
Slice the remaining apples (12 quarters) length-wise very thin. Using a mandolin will be the best way to get consistently-sized slices. If a mandolin isn't available, use a flexible carving knife or very sharp chef's knife. Try to get the slices no more than 1/8"-thick.
Preheat oven to 400° F.
Fill the tart shell with cooled compote almost to the top, leaving about 1/4" of crust exposed. Arrange the sliced apples around the tart in a fanned pattern as in the photo. Depending on the size of your slices, you will probably get one ring of apples around the outside of the tart and be left with a hole in the middle that can be filled with a line of layered apples. If the apple slices are small, it might be possible to do a second ring of apples to completely cover the compote.
Brush apples with melted butter.
Bake for 35-40 minutes, until the apples are brown, but not burnt on the edges. If pastry is browning too deeply, shield it with a ring of foil.
To make the glaze: in a small saucepan, bring the preserves and water (or liqueur if using) to a boil over medium heat, stirring often. Cook about 2 to 3 minutes until thickened. If the preserves contain large chunks of fruit, transfer the glaze to a blender or food processor and process until smooth. Strain the glaze through a mesh sieve into a small bowl, pressing the glaze with the back of a large spoon or rubber spatula to extract as much liquid as possible.
Remove and cool on a cooling rack. Brush a thin layer of warm apricot glaze across the top of the apples, but not the crust.
Serve on its own, or with a dollop of freshly whipped cream.
*Pâte Brisée traditionally has no sugar, although the version linked to here calls for 1 teaspoon. It will certainly work, but I prefer using the sweeter version, a traditional Pâte Sucrée using 3 tablespoons sugar, instead of 1 teaspoon at the beginning of the recipe.