1. Combine the ground cookies, 1/4 cup sugar and the melted butter in a small bowl. Press into the bottom of a lightly greased 9" spring form pan.
2. Beat together the eggs and the remaining 1 c sugar. Add the vanilla and flour and mix to blend thoroughly. Gently whisk in the yogurt. Pour batter into the prepared pan, and bake at 350 degrees for 45-50 minutes or until barely set in center. Turn oven off and cool cake in oven.
3. Bring cake to room temperature, then refrigerate at least 4 hours or overnight. Serve cake with berries.
Citrus: Add 1 Tbsp. orange zest and 2 tsp. lemon zest to the batter
Mocha: use chocolate cookie crumbs in crust and add 1 Tbsp. instant espresso, dissolved, to the batter