A way to avoid having to use a calculator as much is after adding all the ingredients of your recipe to a blank day in the future open fitday again in another window and tile them side by side.
In the new window select "Create A Custom Food" and name it but do not put in any of the info, then select "create this food".
Then change the "Amount:" to the total, either servings or weight, whichever you prefer to use (unfortunately you can't use both unless it's as separate entries), and click "recalculate".
After the page has loaded click "Edit This Food" and enter the info from the Calories and Nutrition tabs of your recipe from the other window.
Once you click "Save This Food" you're done.
All said, I also think a "save as recipe" option is warranted.