About 3/4 cup all-purpose flour
About 1/4 cup (1/8 lb.) butter or margarine, cut into chunks
1/4 cup firmly packed brown sugar
1/4 teaspoon baking soda
1/4 teaspoon ground cardamom
1 large egg yolk
1 cup regular or reduced-fat sour cream
1 large egg
1/2 cup granulated sugar
2 teaspoons cornstarch
1 teaspoon grated lemon peel
2 cups blueberries

1. In a food processor, whirl 1/4 cup flour, 1/4 cup butter, brown sugar, baking soda, and cardamom until fine crumbs form. Add egg yolk and whirl until dough holds together. (Or in a bowl, mix dry ingredients; add butter and rub in with your fingers until fine crumbs form. Add egg yolk and mix with a fork until dough holds together.)

2. Butter and flour a 9-inch nonstick pie pan. Evenly press dough over bottom and up sides of pan to inside edge of rim.

3. Bake pastry in a 325 degree oven until golden, 8 to 10 minutes.

4. Meanwhile, in a bowl, mix sour cream, egg, granulated sugar, cornstarch, and lemon peel until well blended. Stir in blueberries. Scrape mixture into hot pastry.

5. Return to oven and bake until center no longer jiggles when pan is gently shaken, 30 to 35 minutes.

6. Let stand on a rack until cool, about 1 hour. Cover and chill until cold, at least 1 hour or up to 1 day. Cut into wedges.