There is a lot of stuff one can cook without using a knife, but I think my favorite is making butter. Creating basic ingredients is just so satisfying. I also like bread, and when I get really motivated I will make my own bread and butter at the same time for the holidays. Doing that amazes people.
Perfectly cooked eggs (hard, scrambled, poached, and sunny) are a close second.
Next on my list for this summer are clarified butter, fresh pasta, and tortillas.