Don’t worry, this is a common issue, not just with Mexican rice pudding but with any rice pudding recipe. Once you add the milk, evaporated milk and sweetened condensed milk, you will notice it thicken considerably. The longer you simmer this dessert or breakfast, the more you will see it thickens up. Now, this pudding isn’t supposed to be watery thin but it’s not supposed to be solid either. So, if it thickens more than you want, simply add some milk or cream and stir it in to thin it down a little.