How to Make It
In a small bowl, whisk mayonnaise, sour cream, lemon zest and juice, mustard, salt, pepper and paprika. Taste dressing and add sugar, if desired. Place peas, onion and tarragon in a large bowl. Drizzle enough dressing over to coat lightly (you might have extra dressing; cover and chill for up to 3 days) and gently toss to combine. Cover and chill salad for at least 1 hour before serving. Taste and adjust seasoning, if desired.