So we tried making watercress pesto last night. It was good, I must say. Milder than basil pesto. Sorry no pictures. We were so hungry and just completely forgot to document the experiment.
Here's the quick and easy recipe, if you'd like to try it:
Puree in the blender the following:
2 cups watercress (remove the thicker stalks)
Half cup pine nuts (I throw in some walnuts too)
2 Tbsp lemon juice
Slowly add around 6 Tbsp olive oil (add more if sauce is too thick) to the puree.
Add salt and pepper to taste and stir in grated parmesan (I use maybe a cup and a half as we are cheese people).
Will try to put the pesto on baguette slices next time. Yum!