Preheat the oven to 375°F / 190°C. Use a chef's knife to slice off the top ¾-inch/2 cm of each bulb of garlic in a crosswise fashion, exposing the cloves. Drizzle each head with a teaspoon of olive oil. Wrap each bulb in foil and transfer them to a baking sheet. Roast the bulbs for 30-35 minutes, or until the cloves are tender and browning. Set the bulbs aside to cool for 10 minutes.

Add the tahini, water, lemon juice (starting with 1 ½ tablespoons—you can add more to taste once you blend up the sauce), the remaining 2 tablespoons olive oil, nutritional yeast, salt, and pepper to a blender. Invert each of the two roasted garlic bulbs over the blender and squeeze out all of the roasted cloves into the sauce mixture.

Blend the sauce for 1-2 minutes, or until thick and smooth. Transfer it to an airtight storage container. At this point, it can be stored for up to 5 days in the fridge or frozen for up to 6 weeks.

When you're ready to use the sauce, boil your pasta shape of choice according to package instructions. Drain the pasta, reserving about 1 cup / 240ml of the hot pasta water. Return the pasta, along with any add-ins of choice (roasted vegetables, a bean, steamed greens, etc.) to the pot over low heat, along with the sauce*. Add ½ cup / 120ml of the pasta water. Heat and stir to incorporate the sauce into the pasta and serve.

The sauce can be stored in an airtight container in the fridge for up to five days and frozen for up to six weeks.