Whenever possible, use ricotta impastata to make your cannoli filling. Ricotta impastata is drier and smoother than typical ricotta, eliminating much of the water that can lead to problems with the filling. If you are unable to find that variety, drain your ricotta overnight in a strainer lined with cheesecloth. This will allow much of the excess moisture to leave the cheese, making your final product more sturdy and less runny. Give the cheese a final squeeze before preparing the filling. Always use whole milk ricotta, rather than part-skim or skim ricotta, as the fat will separate from the water less in the heavier version.

If your recipe calls for more than about 3/4 cup sugar per 1 pound of ricotta, reduce the sugar. When mixed in a recipe, the sugar will draw out the moisture of the other ingredients and become runny itself, leading to a watery filling. Too high a ratio of sugar to cheese makes the filling runny and it can make it cloyingly sweet. As the cheese is the base of the recipe and provides the bulk of the stabilization, you will not need to replace the sugar if you reduce its quantity in the recipe.

To stabilize your cannoli cream further, consider replacing part of the ricotta with mascarpone, an Italian cream cheese. The addition will reduce the moisture and create an extra-creamy filling. Some pastry chefs prefer mascarpone-based cannoli creams and even go so far as to eliminate ricotta from the dessert altogether. If you cannot find mascarpone, traditional cream cheese will work when blended with ricotta in smaller amounts, as the flavor is stronger than that of mascarpone.

If you already prepared your cannoli filling following a recipe and it turned out watery, you can still salvage the cream. Drain the runny filling, thoroughly squeeze additional whole milk ricotta and add the dry cheese to the mixture. Or, add a bit of mascarpone or cream cheese to the mixture and beat until it stiffens. Alternatively, mix in a small amount of finely ground almonds or pistachios, or dessicated coconut, to the cream until well blended. This method may alter the overall flavor of the cannoli filling, so adjust the amount to taste.