Bring a large pot of salted water to a boil and cook the macaroni according to package directions until al dente—this timing is crucial for the right texture in the final salad. While the pasta cooks, dice the hard-boiled eggs into 1/2-inch pieces, finely dice the shallot, and finely chop the celery. Drain the tuna and set aside. When the pasta is done, drain it thoroughly and rinse with cold water to stop the cooking process and remove excess starch, which helps prevent a gummy salad.

In a large mixing bowl, whisk together the mayonnaise, sweet pickle relish, celery seed, Dijon mustard, salt, pepper, and lemon juice until fully combined and smooth. This dressing base will coat every piece of pasta and create the signature creamy flavor. I prefer to make the dressing before adding the pasta so all the flavors are fully incorporated and balanced.

Stir the drained tuna into the creamy dressing base until evenly distributed. Add the cooled macaroni from Step 1 and fold everything together gently but thoroughly, making sure the dressing coats all the pasta pieces. Work carefully to maintain some texture in the tuna rather than breaking it down too much.

Add the diced hard-boiled eggs from Step 1, diced shallot, and frozen peas (no need to thaw them—they'll soften as the salad sits and chills). Fold everything together gently with a spatula or wooden spoon until everything is evenly distributed. I like to fold rather than stir vigorously at this stage so the eggs stay in nice chunks and the salad has better texture.

Transfer the salad to a serving bowl or container and refrigerate for at least 2 hours before serving. The chilling time allows all the flavors to meld together and the peas to soften to the perfect tenderness. Taste before serving and adjust seasoning if needed—sometimes a tiny squeeze of extra lemon juice brightens it right before guests arrive.