1First, prepare the syrup: mix sugar and water in a saucepan and bring to a boil. Let cool. Add the strawberry (or grenadine) syrup.
2When you start preparing the sponge cake, preheat oven to 400/425 degrees Fahrenheit.
3Place the eggs and sugar in a medium-sized bowl over a double boiler. Keep the water just to a simmer, do not boil. Using an electric whisk, beat the eggs and sugar mixture on medium speed for 5 to 10 minutes. The mixture should double in volume, be pale yellow, and reach the ribbon stage (this means that when you lift the whisk ove the mixture, the batter should fall slowly forming a ribbon that will briefly hold its shape).
4Remove the bowl from over the water bath and gently stir in the sifted flour in increments using a spatula.
5Grease a round pan and sprinkle with flour. Remove excess flour.
6Carefully pour the mixture into the pan and bake it for 15-20 minutes.
7Unmold the génoise (sponge cake) immediately after taking it out of the oven and let it cool on a rack.
8When ready to proceed to prepare the filling, place the cream in the freezer.
9Rinse, hull and cut the strawberries in halves. Set them aside.
10In a bowl, whisk the mascarpone with the milk and sugar until the mixture is smooth.
11Whip the well chilled heavy cream into whipped cream with an electric whisk.
12Gently mix the whipped cream into the mascarpone misture with a spatula.
13To assemble the shortcake, cut the cake in half horizontally.
14Moisten lightly the two discs with syrup using a brush.
15Spread about 1/3 of the mascarpone mixture over one cake disc.
16Place the strawberries on the cream and cover with the second disc.
17Cover the whole cake with the remaining cream and finally decorate it with some of the remaining strawberries. Store at least for one hour in the refrigerator before serving.