for the crust
2 1/2 cups all purpose flour
1 tablespoon sugar
3/4 teaspoon salt
10 tablespoons (1 1/4 sticks) chilled unsalted butter, cut into 1/2-inch pieces
1/3 cup chilled solid vegetable shortening, diced
6 tablespoons (or more) ice water
for the filling
1 pound fresh red currants
3 egg whites
1/2 cup sugar
3/4 cup ground almonds (almond meal)
Blend flour, sugar and salt in processor. Add butter and shortening and cut in using on/off turns until mixture resembles coarse meal. Add 6 tablespoons ice water and process until moist clumps form, adding more water by teaspoonfuls if dough is dry. Gather into ball and then flatten into a disk. Wrap in plastic and chill for a couple of hours.
Position rack in lowest third of oven and preheat to 400F.
Beat egg whites until soft peaks form. carefully fold in sugar and almond meal, trying not to deflate the mass too much. Add in currents.
Roll out dough on floured surface to 12-inch round. Transfer to 9-inch-diameter spring form pan. Fold edge under, forming high-standing rim; crimp. Add filling.
Bake tart for 10 minutes. Reduce oven temperature to 375F. Continue baking until juices bubble thickly and crust is deep golden, covering edges with foil if browning too quickly, about 1 hour.
Cool completely before removing from pan. Serve at room temperature, plain or with whipped cream.
Note: this tart is tart… as in, not very sweet!