Step 1

In a small bowl, whisk the sour cream and mayonnaise until well blended.

Step 2

Squeeze the juice from one lime half into the fish taco sauce mixture, then whisk thoroughly. You'll want the consistency of a pourable, creamy salad dressing. If still too thick, add more lime juice from the other half. If too runny, add sour cream.

Step 3

Add all of the spices, whisking to mix thoroughly. Add the capers, minced pepper and cilantro, and whisk thoroughly.

Step 4

Cover the bowl with wrap and refrigerate the fish taco for at least one hour — the longer the better.

Step 5

Serve chilled. Spoon white sauce over fish tacos, or add into taco salads or rice bowls.