Preheat oven to 300 degrees. Toast pistachios in the oven until crisp but not brown, about 15 minutes. When cool enough to handle, rub pistachios between your hands or towels to remove the outer skins, then grind them finely in food processor. Add the flour, soda, and salt, and process briefly.
Butter and flour a 10-inch springform pan. Increase oven temperature to 350 degrees.
In a mixer, beat the egg yolks with 1/2 cup of the sugar until pale yellow and thick ribbons. Mix in the yogurt, then the olive oil. With a spatula, fold in the reserved flour mixture.
Beat the egg whites to soft peaks, add remaining 3/4 cup sugar and beat to stiff peaks. Fold egg whites into the batter. Pour batter into prepared pan and bake 45 to 55 minutes, or until done. Cool on a rack, remove from pan and serve with drained yogurt, honey and chopped pistachios.
c.1997, M.S. Milliken & S. Feniger, all rights reserved