Rustic Jam Shortbread Tart

from Melissa Clark's Cook This Now:

zest of 1/2 lemon
1/4 cup of whole almonds
3/4 cup unbleached all-purpose flour
1/4 cup sugar
generous pinch of salt
6 T cold unsalted butter, cut into 6 chunks
1 large egg yolk
1/2 t almond extract
3/4 cup jam

Preheat the oven to 400 degrees. But a 9 inch round cake or tart pan. With food processor running, drop in the lemon zest and almonds, and grind them fine. Scrape down the sides, add the flour, sugar, salt, butter, egg yolk, and almond extract. Pulse.

Turn pastry dough into pan. pat out evenly. Bake for 13-16 minutes. Remove from oven and turn the heat up to 500 degrees. Spread the jam over the tart. Bake for 5-10 minutes. Cool on rack and serve warm (not hot).