Start by hard-boiling the eggs if not already done—place them in cold water, bring to a boil, then remove from heat and let sit covered for 10 minutes before cooling and chopping into 1/2-inch chunks. While the eggs cook, finely dice the onion into 1/4-inch pieces and soak it in 1/2 cup of water for about 5 minutes to mellow its sharp bite and add a subtle sweetness to the salad. Dice the peppers into bite-sized pieces, roughly 1/4-inch to match the texture of the other ingredients. Shred or cube the Irish cheese into small, even pieces so it distributes evenly throughout the salad.

In a separate bowl, whisk together the mayo, relish, mustard, salt, thyme, and black pepper until smooth and well combined. The relish will add a subtle tang and texture that complements the creamy base. I like to taste the dressing at this point and adjust the seasoning if needed—a pinch more salt or mustard can really bring everything together.

Drain the soaked onion completely and add it to a large bowl along with the peas, chopped eggs, diced peppers, and cheese. Gently fold these ingredients together to distribute them evenly. Pour the dressing from Step 2 over the salad and fold everything together until all the ingredients are well coated and the dressing is evenly distributed. I find folding rather than stirring helps keep the ingredients intact and prevents the salad from becoming mushy.

Transfer the salad to a serving dish and refrigerate for at least 30 minutes before serving. This chilling time allows the flavors to meld together beautifully and gives the salad a refreshing, crisp texture that makes it perfect for serving alongside traditional Irish fare or as a standalone side.