Huancaína is a creamy, golden-toned sauce made by pureeing sautéed onion, queso fresco (a fresh, crumbly cheese with a mild, milky flavor), milk or cream, and ají amarillo (a variety of chili commonly used in Peruvian cooking). The sauce has myriad uses. Pairing it with boiled potatoes and hard-cooked eggs yields a popular Peruvian appetizer, papa a la huancaína. It’s also much loved over pasta, a dish known as huancaína con fideos. For our simplified version, instead of ají amarillo—which can be tricky to source—we use a combination of habanero chili for heat and yellow or orange bell peppers for sweetness and substance. The creamy, salty, spicy-sweet sauce on al dente noodles, garnished with briny black olives (botija olives are classic, but we use widely available Kalamatas instead) is addictive. For fans of spicy heat, leave some or all the seeds in the habanero.