Instructions
1Bring a large pot of well-salted water to a boil and cook the pasta to al dente. Drop the whole peeled garlic clove into the water with the pasta and fish it out after 2 min β a raw clove blended into an uncooked sauce is harsh enough to bulldoze everything else, and 2 minutes in the water fixes it completely. Before draining, scoop out a full 2 cups of the pasta water; you need it for the sauce, so set a mug in the colander now so you don't forget.
2Make the sauce while the pasta cooks. Put HALF the beans, the blanched garlic clove, the lemon zest (hold back a pinch for the table), half the lemon juice, the 1 tbsp olive oil, and Β½ cup of the hot pasta water in a blender. Fill it no more than halfway and leave the center cap out with a towel over the top β hot liquid builds steam and will pop a sealed lid. Blend 45β60 seconds until it is completely smooth and pourable, like cream, with no grit left; add more pasta water a splash at a time if it's too thick to pour. Leave the Parmesan OUT of the blender: hot water plus hard cheese in a blender turns stringy and grainy. It goes in at the pan instead, where the starch melts it smooth. (No blender? An immersion blender in a deep jar or a food processor both work. A fork does not β the whole point is that it goes completely smooth.)
3Heat the 2 tbsp olive oil in your largest skillet over medium-high. Add the zucchini, yellow squash, and bell pepper and spread them out β if the pan is packed, do the squash in two batches or they'll steam grey instead of browning. SautΓ© 5β6 min, stirring only every minute or so, until they're browned at the edges but still have bite. Do NOT salt them until they're browned: salt early pulls the water out and you lose all the color.
4Add the sliced garlic and cherry tomatoes and cook 2 min more, just until the tomatoes slump and the garlic smells sweet. Stir in the remaining whole beans to warm through.
5While the vegetables cook, make the salad dressing: whisk the olive oil, lemon juice, Dijon, and a pinch of salt in the bottom of a serving bowl and pile the greens on top β don't toss until you sit down.
6Drain the pasta and return it to its own empty pot off the heat β the skillet will not hold 12 oz of pasta plus all those vegetables. Scrape the vegetables and beans in on top, pour the blended bean sauce over, and add the Parmesan. Toss constantly over LOW heat for 1β2 minutes until the cheese melts in and every noodle is coated, loosening with more pasta water as needed; it thickens fast off the heat. Keep it low β a hard boil or a ripping-hot pan is what makes the cheese go grainy.
7Off the heat, stir in the remaining lemon juice and season with salt and plenty of black pepper. Finish with the torn basil and the pinch of lemon zest you held back, toss the salad, and serve with extra Parmesan at the table. (Leftovers: the bean sauce sets up firm in the fridge β reheat with a good splash of water or milk and it loosens right back up.)