In a jar with a tight-fitting lid, combine the olive oil, red wine vinegar, lemon juice, and Dijon mustard. Add the oregano, basil, garlic powder, onion powder, salt, red pepper flakes, and black pepper. Seal the jar tightly and shake vigorously for 30 seconds until the dressing is well emulsified and the spices are evenly distributed. Set aside at room temperature while you prepare the other components.

Bring a large pot of salted water to a rolling boil. Add the rotini and cook according to package directions until al dente—this usually takes 8-10 minutes. I like to taste a piece about a minute before the recommended time to catch that perfect tender-but-still-firm texture. Drain the pasta in a colander but do not rinse it; the starch on the surface will help the dressing adhere better to each piece.

While the pasta cooks or immediately after draining it, dice the pepperoni into bite-sized pieces, chop the sun-dried tomatoes into 1/4-inch bits, crumble or dice the feta cheese, and finely chop the fresh parsley. For the mozzarella pearls, you can leave them whole—they'll soften slightly as they sit in the dressing. Arrange all prepped ingredients in separate small bowls so they're ready to combine.

Transfer the drained pasta to a large mixing bowl. Pour the dressing from Step 1 over the warm pasta and stir well to coat every piece. Add all the prepared ingredients from Step 3—the pepperoni, sun-dried tomatoes, cucumber, feta, mozzarella pearls, kalamata olives, parmesan, and fresh parsley—and fold everything together gently but thoroughly. I find using two spoons to toss works better than a fork, which can break the pasta and mozzarella pearls.

Transfer the pasta salad to an airtight container or cover the bowl tightly with plastic wrap. Refrigerate for at least 8 hours, preferably 12 hours, which allows the flavors to meld together and the pasta to fully absorb the dressing. The cold temperature also helps the mozzarella pearls firm up slightly, giving them a better texture.

Remove the pasta salad from the refrigerator and give it a good stir to redistribute any dressing that may have settled at the bottom. Taste and adjust seasonings if needed—sometimes a small pinch of extra salt or vinegar brings everything into balance. Serve cold or at room temperature, and store any leftovers in an airtight container in the refrigerator for up to 3-4 days.