Caramel Apple Tart

This recipe contains footnotes, but to generate them properly you must enable JavaScript in your browser (otherwise, they'll be embedded in the text in square brackets). Hope that's not inconvenient—I think asciidoc's footnote generator is worth it.

This is simply a shortbread crust topped with fresh apples drizzled with a pungent, almost bitter, burnt-sugar caramel sauce.

Shortbread Crust:

½ cup (1 stick) unsalted butter, room temperature
¼ cup confectioner’s sugar
1 cup flour
⅛ teaspoon salt

Filling:

4 cups fresh apples, peeled, cored, sliced relatively small, tossed with
1 or 2 teaspoons lemon or lime juice or cider vinegar

Caramel Sauce:

1 cup sugar
¼ cup (½ stick) unsalted butter
⅛ teaspoon cream of tartar
⅛ teaspoon salt
tiny amounts of milk or cream

You can bake the crust either in a classy tart pan or simply in an 8 x 8 inch baking pan.

In a tart pan:
1. In the mixer, beat the butter and sugar until creamy. Add flour and salt and beat until the dough just starts to form clumps.
2. Press the dough into the bottom and sides of the tart pan.
3. Place the crust into the freezer for 15 minutes.
4. Preheat oven to 425°F.
5. Bake until golden brown (about 13-15 minutes) then remove from oven to a cooling rack.
In a square pan:
1. Preheat oven to 350°F.
2. Optionally, line the baking pan with parchment paper
  [I fold a large square into a box shape, then crimp the edges over the sides of the pan.]
  .
3. In the mixer, beat the butter and sugar until creamy. Add flour and salt and beat until the dough just starts to form clumps.
4. Press the dough into the bottom of the pan.
5. Bake until lightly brown around the edges (about 18-20 minutes) then remove from oven to a cooling rack.

Once the crust is baked, you can turn the oven off. While the crust is baking, make the caramel sauce:

Place half the sugar into a saucepan.
Find a basin large enough to immerse the bottom of the saucepan and place it in the sink. Cover the bottom of this vessel with cold water.
Carefully melt the sugar over high heat, stirring with a wooden spoon and tilting the pan to ensure the sugar melts uniformly.

Melted sugar smokes and burns easily and can spit, causing painful burns. Wear appropriate clothing and be prepared to move the saucepan to the sink quickly and safely.
Soon the sugar will turn golden, then rapidly darker. Every second counts here. Before it turns black and starts spewing smoke, carry the saucepan to the sink and gently immerse the bottom of the saucepan in the cold water. Be prepared for some steam, sound, and fury. Once the burnt sugar has settled down, it will line the saucepan like a layer of volcanic glass. This is normal.
Return the saucepan to the stove on medium heat and add the remaining sugar, butter, cream of tartar and salt.
Bring to a boil, stirring constantly, until ingredients merge into a uniform mass.
Add very small amounts (teaspoons) of milk or cream to get the ingredients to dissolve, and cook until adequately thick
[See what I did there? Yes, doing this right involves a candy thermometer or at least a cup of cold water, but I like that every batch comes out a bit different, sometimes chewy, sometimes runny, sometimes with crunchy toffee bits floating in it. In any case, the juice from the apples will eventually liquefy and diffuse it.]
. Beware, this is still very hot and will blister the incautious taster.
If the sauce is thin enough, spread some of it over the crust, being careful not to tear it; shortbread’s fragile!
Press the apples into the pan, then pour or spoon the sauce over all the apples as evenly as you can.

You can serve this as soon as the pan has cooled since the apples will quickly cool the caramel, or you can chill it in the refrigerator. Doesn’t really need any accompaniment, but ice cream or whipped cream never hurts.

History:

It was apple season and, with a big box full from our local orchard, I’d been trying some great pie recipes and experimenting with some of my own. I made one with dulce de leche that, while tasty enough, lacked the intense caramel flavor I crave. I started thinking about flan and burnt sugar. A friend who loves my autumn olive bars thought that the shortbread crust would be just the thing.