There are a few key ingredients that I use in my stuffed shells to amp them up a bit. First, I use basil...and lots of it. Basil is definitely my favorite herb to cook with, especially in Italian dishes. It adds a bit of a minty/lemony taste but still clean at the same time. In my personal opinion, nothing screams Italian food like basil. My second addition is roasted or fire roasted tomatoes (you can roast them yourself or buy them by the can). Its an INCREDIBLE flavor booster for any marinara sauce. My third addition is red pepper flakes. The red pepper flakes give the sauce a nice little back heat - not too much, just subtle enough to feel/taste it as you finish your forkful of goodness. The last addition I add to my shells is alfredo sauce.
you read that right - alfredo sauce.
But I don't add this into the marinara, I layer it onto my shells before layering on the marinara sauce. You wouldn't believe how much flavor this adds to the end result, but trust me, it is WELL worth the additional ingredients.
This is probably one of my best Italian recipes so I'll be HAPPY to share it with you if you would like to try it yourself, just hit me up and I'll toss the list of ingredients and the how-to list your way. Be warned, it is a labor intensive dish, but on the plus side - it is fantastic and it will easily feed 4-6 people or 2 people with plenty of left overs.