Place potatoes in a 4-quart Dutch oven. Add enough cold water to Dutch oven to cover potatoes by 5 inches. Bring to boiling; reduce heat. Simmer, uncovered, about 12 minutes or until potatoes are fork-tender but not falling apart.Advertisement
Add kale to potatoes in Dutch oven. Stir and cook 30 seconds; drain. Return potatoes and kale to the Dutch oven. Cook, uncovered, over low heat 3 to 4 minutes to evaporate excess moisture, stirring gently. Remove from heat; cool completely.
In a large bowl whisk together onion, parsley, vinegar, sour cream, mayonnaise, mustard, pepper, celery seeds and celery salt. Fold chopped egg into sour cream mixture. Fold in potato-kale mixture. Serve immediately.
To make ahead: Cover and chill for up to 12 hours.
1 vegetable, 1/2 starch