Cook the pasta: Bring a large pot of salted water to a boil. Cook pasta until just al dente. Drain, rinse under cold water until cool, and toss with a splash of olive oil to stop sticking.

Prep the mix-ins: While the pasta cooks, chop the crab, celery, red bell pepper, red onion, dill, and green onions. Thaw peas by running under cool water and draining well.

Make the dressing: In a large bowl, whisk together mayonnaise, sour cream (or yogurt), Dijon, lemon zest, lemon juice, Old Bay, garlic powder, sugar or honey, salt, and black pepper. Adjust lemon and salt to taste.

Combine: Add cooled pasta to the bowl of dressing. Fold in crab, celery, bell pepper, red onion, peas, green onions, dill, and capers if using. Mix gently to avoid breaking up the crab too much.

Chill: Cover and refrigerate for at least 30–60 minutes. This lets flavors meld and the dressing cling to the pasta.

Final seasoning: Before serving, taste and adjust with more lemon, Old Bay, salt, or pepper. If the salad tightened up, loosen with a spoonful of mayo, yogurt, or a splash of milk.

Serve: Garnish with extra dill or green onions. Serve cold or cool, alongside grilled corn, tomatoes, or a simple green salad.