4.2 oz. of dry mix should be ~420 Cal. or a bit more if the water-only mix has some fat incorporated to make up for the oil you don't add. Good rule of thumb I learned is carbohydrates (sugars, starches, grains, pasta, flour, crackers, etc) = 100 Cal./oz.; protein = 100 Cal./oz.; fats and oils = 240 Cal./oz. I figure if the food is pliable (like bread, tortillas, salami, or jerky) there's usually some water content, so the calorie density is a bit less than whatever the dry components are. Nuts are great, tho'--high oil content, so sunflower seeds for example are 176 Cal./oz. I'm still doing a lot of reading in these forums and elsewhere to try to get a good nutritional balance, in addition to high calories.
I don't cook in the backcountry (just boil and rehydrate) but pancakes with pinenuts and huckleberries fried in ghee sounds mighty tasty.