Prepare the pastry cream:Mix the egg yolks and sugar together.Add the cornstarch and dilute completely.Heat the milk to boiling point.Pour the boiling milk over the egg yolk mixture and whisk vigorously to avoid lumps.Pour the mixture back into the saucepan and bring to the boil again. Add the food coloring. Set aside off the heat.Fill a pastry bag with the cream and pipe into glass cups.Arrange the mini-eclairs, pour the coulis, and decorate with fruit and lemon balm. The citrus flavor of the lemon balm pairs perfectly with this dessert.