Step 1Combine the strawberries, sugar and vanilla in a bowl about 3 hours before serving. Gently toss until mixed. Let sit at room temperature.
Step 1Line a 9-inch pie plate with the pound cake slices, very slightly overlapping. Use plastic wrap to flatten the cake with your hands and compact it into the plate. Trim the top edges as needed. Freeze until solid, about 3 hours.
Step 2Spoon the ice cream into the frozen cake shell. Smooth the top, shaping it into a dome. Freeze until hard, 2 hours.
Step 3Use a mixer with a whisk to beat the egg whites, sugar and cream of tartar to stiff peaks, 2 to 3 minutes. Spread the meringue over the hard ice cream; swirl with a spoon to make a decorative pattern. Alternately, spread a 1/2-inch thick layer of meringue over the hard ice cream; smooth with a long spatula. Then spoon the remaining meringue into a pastry bag with a large star tip; decorate the top with large rosettes.
Step 4Place a rack about 7 inches under the broiler element; heat the broiler.
Step 5Broil the pie until the meringue is golden, 6 to 8 minutes. Alternatively, use a propane torch. Freeze the pie 1 hour. (This can be kept frozen and covered loosely with plastic wrap up to 5 days.)
Step 6To serve, take the pie from the freezer 20 minutes before serving. Cut into wedges. Pass the sauce separately.