Butter the bottom and sides of a 9-inch springform pan. Cover bottom of pan with pieces of frozen pound cake, cutting pieces to fill in any gaps.

Blend softened ice cream with pureed blueberries and graham cracker crumbs. Spread ice cream mixture over pound cake pieces. Cover tightly with plastic wrap and freeze at least 4 hours (up to 24).

Heat oven to 450°.

Whip egg whites with cream of tartar and salt until foamy. Add vanilla extract and beat until soft peaks form. Gradually add sugar and whip until peaks are stiff and glossy.

Remove cake base from pan. Spread meringue over ice cream base (use an offset spatula to make dramatic swirls), or use a pastry bag to pipe it. Place in oven 4 minutes or until meringue is evenly golden brown. If you prefer, use a kitchen torch instead of the oven to get even coloring.