Break the cake up into walnut-size pieces.

Sprinkle the gelatin over 1/2 cup cold water and set aside.

Combine the lemon juice, 3/4 cup of the sugar, 2 tablespoons of the lemon zest, and the egg yolks in the top of a double boiler and cook over hot water, stirring, until the mixture coats the back of a spoon. Stir in the gelatin mixture and set aside to cool.

Beat the egg whites until they are foamy. Gradually beat in the remaining 1/2 cup of sugar until the mixture is stiff. Fold into the cooled yolk mixture along with the angel food cake pieces. Spoon the mixture into a 9-inch springform pan and refrigerate at least overnight. To serve, whip the heavy cream. Remove the ring from the springform. Top the cake with whipped cream and sprinkle with the remaining tbsp of grated lemon zest and a few strawberries.