Line 6 (3-inch) metal or pipe molds with parchment paper, having the parchment come 3 to 4 inches over the top of the mold (it should look like a mold for a frozen souffle).

Chill the bowl and wire whip of an electric mixer in the freezer.

In a small saucepan combine the lemon juice, 2 tablespoons simple syrup and gelatin. Stir to soften the gelatin. Place over low heat and cook until the gelatin dissolves, stirring constantly. Remove from the heat and pour into a mixing bowl.

Remove the bowl and whip from the freezer and add the heavy cream. Whip the cream until soft peaks form. Combine the gelatin mixture and lemon curd. Mix well. Add the lemon mixture to the whipped cream. Continue to beat until the cream forms stiff peaks.

Brush the sponge cake with the remaining 1 cup of simple syrup.

Using a 3-inch round cutter, cut the cake into 6 rounds. Place a cake round at the bottom of each of the molds. Spoon 1 cup of the mousse on top of each cake. Cover the molds with plastic wrap and refrigerate for several hours or overnight until the mousse is firm. Remove the molds from the refrigerator and carefully remove the ring molds and parchment paper. Place the cakes on serving plates. Garnish with the whipped cream and mint.