Start making your pumpkin custard mixture first.
In a large bowl, combine the pumpkin puree, evaporated milk, sweetened condensed milk, cream cheese, sugar, eggs, cornstarch, cinnamon and vanilla essence.
Start making your caramel.
In a medium saucepan, add sugar, water and cream of tartar. Cook over medium heat, stirring constantly, until sugar is dissolved, about 2-3 minutes.
Increase heat and boil, without stirring, for about 10 minutes, until caramel turns a light amber brown color
Remove from heat and quickly pour the caramel in your mold. Swirl it as quickly as you can around it to coat the sides too.
Pour over the pumpkin custard mixture.
Arrange the molds in a large deep roasting pan and pour boiling water until it comes about halfway up the side of your flan mold.
Bake at 300F for 50-60 minutes or until knife inserted near center, comes out clean.
Remove from the oven and allow to cool for about 30 minutes