Make the cake mis as directed on the package for cupcakes. Using cupcake foil is easy clean up. bake according to package directions and let cool.
In a food processor combine the mascarpone cheese, raspberries, 1/4 sugar, and lemon juice. Process the mixture till smooth. Transfer the raspberry mixture to a pastry bag fitted with a small tip. Push the tip gently into the top of the cupcake, and squeeze in the mixture till the cupcake plumps. Continue with all cup cakes.
In a small saucepan bring 1/2 cup sugar, water, and vanilla extract to a simmer over medium heat. Simmer until the sugar is dissolved. In a medium bowl combine the vanilla syrup with the confectioner's sugar. Stir until smooth. Working quickly, dip the top of the cupcake into the icing, lightly shaking off additional icing, and allow to set.