To make the sponge cake, take eggs out of refrigerator at least one hour before using. In a small bowl, sift flour, baking powder,salt, and 1 cup sugar.
In a large mixing bowl, combine egg whites and cream of tartar. Beat until soft mounds form then add ½ cup sugar, 1 tablespoon at a time, and beat until stiff peaks form.
Combine egg yolks, water, and vanilla. Stir into flour mixture. Beat a minute or two, until well blended. Fold egg yolk mixture into stiff egg whites until blended.
Spray two, 11-inch flan tart pans with non-stick cooking spray. Fill each pan about ⅔ full. Shake until batter is evenly spread. Bake at 375°F for 8-10 minutes, or until cake is golden brown. Invert pan and cool completely before filling.
To assemble the tart, spread ½ cup chilled pudding in each tart cavity. Arrange sliced strawberries on pudding until cavity is covered, overlapping fruit as needed. Spoon Dr. Oetker cake glaze over fruit until completely covered. Refrigerate for at least one hour before serving.
Note: To make a glaze from scratch, mix one package unflavored gelatin with one teaspoon of fruit juice until dissolved. If desired, add sugar. Cook until gelatin mixture is dissolved. Remove from heat. Refrigerate until mixture is thick. Spoon over fruit.