How to plan the portion size for a vegetarian bourguignonne dish? I like the taste of beef bourguignonne and would like to create a vegetarian version of it. For that, I plan to use oven-dried, tempura-fried aubergine slices instead of meat (egg-containing tempura, fried to a golden crust), and mushroom stock for the sauce. 

The problem is that I am not sure how filling this substitution will be, and how many calories it contains - the aubergines probably close to nothing, but the fried tempura is rich. 

How should I go about calculating the portions, so they are roughly equivalent to a portion of standard beef bourguignonne?
For bourguignonne, most of the calories are going to be in the noodles anyway.  The beef amounts for bourguignonne are smallish, and the flavorings (mushroom, possibly carrot, broth, wine) are pretty much non-existent nutritionally.

I would just go by mouth-feel.  Cut the aubergine in amounts that approximate the texture and flavor of the original dish, and don't much care about the differences.