The texture should be smooth and pourable - not too thick, not watery. The color should be deep golden-orange from the ají amarillo. If your sauce looks pale yellow, add more paste. If it's clumping, add more evaporated milk and blend again.
Boil yellow potatoes (Yukon Gold or similar) until tender, about 20 minutes. Slice into rounds. Arrange on a bed of lettuce leaves, pour huancaína sauce generously over the top, and garnish with halved hard-boiled eggs, black olives, and a few slices of fresh tomato. Serve cold as a starter.
Cost per serving as a starter: roughly $1.20-1.80 depending on cheese prices in your area.
Cold pasta salad: toss cooked penne with huancaína sauce, cherry tomatoes, and black olives. Works as a packed lunch. Dipping sauce for baked zucchini fritters or roasted vegetables. Sauce for grilled chicken - spoon it over pan-roasted chicken thighs warm from the pan.
Using reduced-fat queso fresco drops this to about 100 kcal per serving with minimal change in flavor.
Replace half the queso fresco with low-fat cottage cheese and blend thoroughly. The texture is slightly less rich but the flavor holds up. Replace evaporated milk with regular whole milk if you want to cut calories further - the sauce will be slightly thinner.
Keeps in the fridge for up to 4 days in a sealed container. Stir before serving as it can settle. Does not freeze well - the cheese texture breaks down on thawing.
Make a batch on Sunday. Use it as a sauce through the week - potatoes Monday, pasta salad Wednesday, over grilled chicken Friday. For more Peruvian sauces and a broader look at South American cooking, see our complete guide to South American condiments.