You are baker, correct? That is a little more precise.
I keep a a sheet of paper taped to the inside of my cabinet at home, and laminated on the wall in the baking area of my kitchen at work. It gives a conversion for 1/3 cup to tablespoons (5 1/3); 1/2 cup to 8 tablespoons, etc. You can break most ingredients from cups to tablespoons. But you want to look at the eggs and the quantity required, as a basis for how far you can reduce the recipe. Then depending on the recipe, quantify to use one egg. Or if the recipe process will allow; beat your egg in a small dish and spoon in half.
The most precise way is to weigh everything, but for some of the common recipes that we use in this country, we have to start by weighing and converting everything. That becomes a little involved for most of us; but the conversion to tablespoons will get you by.
Here's a good page, go to: Italian Food Forever - Italian Recipes!
on the bottom right you can link to a page on conversions.
Here's another one I'd saved. GourmetSleuth - Kitchen Conversion Calculator