I use a spoon. I carry a pocket knife, too, but rarely use it in conjunction with eating on the trail, unless I'm day hiking and brought an apple I want to core.
Recently I bought a Sea-To-Summit aluminum spoon. Before that I used an REI "lexan" plastic soup spoon and it worked very well, except that once I got a hairline crack in the bowl of it in the middle of a weeklong hike. Now with the aluminum spoon I don't worry about breakage or meltage. The broader bowl of a soup spoon seems to be nicer than a teaspoon for me.