My passion for pesto knows no season, but of course now is prime time for basil, in the Northeast at least. Lucky for those of like minds, Epicurious offers almost 250 pesto recipes of one sort or another, whether for pasta, or as a panino’s best friend, or slathered atop grilled halibut on a bed of bright arugula. Even when speaking strictly of basil pesto–leaving aside the mint, arugula, broccoli rabe, and other green forms of the paste–the variety of methods and ingredients in this Liguria-inspired sauce is enough to spark passionate arguments among purists. Pesto plurality has been a good thing in my case, though, now that I’ve deliberately gone back to the books on pesto in recent summers. A few years ago, I began to feel that I’d lost my groove with my own tossed-together version of this summer staple, and I decided to undertake some pesto re-education. First stop was Marcella Hazan, and I dutifully made and remade the Blender Pesto in her Classic Italian Cookbook–a longtime touchstone–searching for the Proustian pesto of my youth. Maybe the secret was the way she beats the cheese and then the butter in by hand at the end, I thought. For a while this version did seem to do the trick, especially when served the really old-fashioned way, with potatoes and green beans to hearty things up. Then last summer, my colleague Kemp Minifie’s pesto won me over in a big way. A cup of parsley to two of basil really makes the flavor pop, and the pepitas she uses suit me better than pine nuts ever did. And Kemp’s recipe explains the essential step it took me too long to learn: introducing some of the pasta cooking water into the pesto, to thin it and warm it and marry it with the pasta. Trying new recipes has gotten me out of my rut. Now I’ve got several pestos I like, and I’m back tossing things into the food processor and experimenting more confidently. Last week, living dangerously, I reversed Hazan’s rule and threw right into the maw of the machine a hunk of yellow Irish sweet butter. To my delight, this pesto came the closest yet to the slightly creamy, bright-green mixture I’d been searching for, vivid in flavor yet mild on the tongue. Speaking of mellow, I just discovered a surprising footnote to Johanne Killeen and George Germon’s recipe for Linguine with Classic Ligurian Pesto in their On Top of Spaghetti…: “A little milk softens and mellows pesto, taking away any hard edges.” In a recipe scaled to a pound of pasta, the authors offer the option of folding a tablespoon or two of whole milk into the pesto along with the softened butter. Has anyone tried that? What’s the gold standard in the green stuff for you? Basil, parsley, both? Pine nuts, pepitas, or nut-free à la pistou? Blender? Food processor? Anyone swear by a mortar and pestle?