Pesto

Pesto is one of sK's favorite, but he only accepts the traditional one:
Basil + pine nuts. ( like Special K, he only gets the orignal flavor :)

Actually, there are various versions. Basically, we need a green, a nut, garlic, olive oil, cheese( Parmesan Reggiano/Pecorino Romano), lemon juice, salt, pepper( black/white)

Green( pick up one or any combination)
Mild: spinach, Boston lettuce, parsley(it is in the middle)

Spicy: basil, arugula, cilantro, tarragon

[Note:
1. I have tried parsley, arugula, cilantro, tarragon, i like the tarragon+parsley one more. tarragon has special aroma, very impressive
2. cilantro version, a good spread for quesadilla]

Nut:
Pine nut, walnut, pecan,

Tips:
1. Olive oil can adjust the thickness
2. Cheese is salty itself, also Pecorino Romano is sharper than Parmesan . so it is better to use with mild green.