Bring a large pot of salted water to a boil. Prepare an ice bath by filling a bowl with cold water and ice.

Blanch basil in boiling water for 20 seconds, then quickly transfer to an ice bath to stop the cooking. This extra step of blanching the basil will result in a brighter green color, a cleaner flavor, and help prevent the pesto from oxidizing. Once cool enough to handle, squeeze out the excess water.

If using whole blocks of cheese, cut into pieces and place them right in the blender or food processor, then pulse until finely grated. If you are grating extra cheese for topping, do this first, then spoon out the extra cheese and set aside.

Add pine nuts, garlic and yogurt to blender along with blanched and drained basil. Pulse until coarsely chopped, then add olive oil and blend until smooth. If pesto is too thick, add a splash or two of pasta water to help thin it out. Taste, then season with salt and pepper as desired (the cheeses are salty enough you may not need to add extra).

Smear a generous spoonful of pesto in the bottom of each serving bowl. Using a large slotted spoon or mesh skimmer, remove pasta from water and place directly into bowls on top of pesto (it's ok if they are not drained dry, the extra bit of water will help the loosen the pesto and coat the pasta easier). Toss to coat. Top with a bit of grated cheese, if desired, and serve warm.

Any leftover pesto can be refrigerated in an airtight container for 2 to 3 days, or frozen in a zip top bag (squeeze out as much of the air as you can) for up to 6 months.