Cook pasta according to package directions in a large pot of salted boiling water until al dente. Drain well, rinse with cold water to stop cooking, then drain again thoroughly. Toss with 1 tablespoon of olive oil to prevent sticking and set aside to cool completely.

While the pasta cooks, blanch the asparagus: Bring a small pot of water to a boil. Add the cut asparagus and cook for 2-3 minutes until bright green and tender-crisp. Immediately transfer to an ice bath to stop cooking, then drain well. Set aside.

In a large bowl, combine the cooled asparagus, thawed peas, halved cherry tomatoes, sliced radishes, and diced red onion. Set aside.

In a medium bowl, whisk together the mayonnaise, Greek yogurt, fresh lemon juice, chopped fresh dill, chopped fresh chives, garlic powder, salt, and black pepper until smooth and well combined. Taste and adjust seasoning as needed.

In your chosen clear serving dish (trifle bowl or glass bowl), begin layering. Start with approximately half of the cooled pasta, spreading it evenly across the bottom.

Spoon about one-third of the dressing over the pasta layer, spreading gently.

Next, evenly spread half of the mixed spring vegetables over the dressing.

Sprinkle half of the crumbled feta cheese over the vegetables.

Repeat the layers: add the remaining pasta, then another one-third of the dressing, the remaining mixed vegetables, and finally the remaining feta cheese.

Spoon the final one-third of the dressing on top, spreading it lightly. You can garnish with a little extra fresh dill or chives if desired.

Cover the salad tightly with plastic wrap and refrigerate for at least 2 hours, or ideally 4-6 hours, to allow the flavors to meld and the salad to chill thoroughly.