Any help will do? You mean any help that comes while you are involved in making this particular batch of brownies? Or any help, whenever the heck we get to it? (Because it's now several weeks after you asked your question….)

One of the primary uses for evaporated milk is to reconstitute it to whole milk, so yes, mix a solution of half evaporated milk and half water and use that in your recipe. A persnickety taster might notice a somewhat cooked flavor in even the diluted evaporated milk (and which is very noticeable in undiluted evaporated milk), but in the context of a flavorful cappuccino icing on flavorful chocolate brownies, we doubt you will be disappointed.

The bit that surprises us the most is that your recipe calls for 3 teaspoonsful – three teaspoons which equals exactly one tablespoon. Whenever we see something like that in a recipe (essentially three opportunities to spill ingredients instead of one) we wonder what the recipe writer was thinking, or why the recipe writer was not thinking. We often come to the conclusion that the writer was not very experienced in the kitchen, which occasionally leads us to think that perhaps we should be looking for a more dependable recipe before we begin looking for substitutes for ingredients we appear to be lacking.

It could also be an old family recipe, or a tried-and-true recipe from a friend, etc. It can be fine to have little inconsistencies here and there in recipes from trusted sources, but we get discouraged – and many of our readers get discouraged – when they try recipes for the first time from an untested source and it flops. We encourage people to be adventurous cooks and eaters, but, with so many good cookbooks, magazines, Web sites, and recipes out there, you might want to be willing to walk away from a questionable recipe rather than sink your time, ingredients, and expectations into it.

That's one reason we always read through a recipe before we start to cook from it. The other, of course, is to verify that we have all the necessary ingredients on hand, unless we have several weeks to wait for an answer about making a substitution….