Beat the cream cheese, lemon zest and juice, vanilla, and sugar together until very smooth. Mix in the sour cream. Sprinkle the gelatin over the water in a small bowl and set aside for 5 minutes. Warm in the microwave for 30 seconds (or in a saucepan over medium heat) and stir to dissolve. Quickly mix into the cream cheese mixture. Fold the whipped cream into the cream cheese mixture.

Pour 1/2-inch of this filling into each of 24 ice-cube compartments. Freeze 15 minutes to firm up. Meanwhile, cut the strawberries in half. Place a strawberry half in each compartment. Pour the filling over the berries to cover and fill each compartment to the top. Freeze at least 3 to 4 hours. (The recipe can be made up to this point, wrapped, and kept frozen up to 3 days in advance.)

Stir together the crushed wafers and walnuts on a plate. When ready to serve, pop out the croquettes and roll in the crumb coating. Place in frilled paper cups or stick each one with a toothpick, and serve.