Matt is right. A quick google search showed 1 Cup of lard has 1,849 calories, and 1 Cup of butter has 1,628 calories, probably because of the added water. The concept holds, however, that the more fat in your food per weight, the more calories. Popular fat additives for backpacking are cheese, nuts, and packets of olive oil.
About the pesto sauce above - check Sarah's freezerbagcooking website to see one of her latest recipe posts for backpacking pesto sauce.