Bring a large pot of salted water to a boil and cook the pasta until al dente. I avoid overcooking because the pasta will absorb some dressing later. Drain and rinse briefly with cool water so it doesn’t stick together.
While the pasta cooks, I chop the tomatoes, cucumber, onion, olives, and roasted red peppers. Keeping the pieces bite-sized makes the salad easier to eat. I set everything aside in a large bowl.
In a small bowl or jar, I combine olive oil, red wine vinegar, Dijon mustard, garlic, oregano, salt, and pepper. I whisk or shake until it looks smooth and slightly thickened. This dressing smells amazing right away.
Once the pasta has cooled slightly, I add it to the bowl with the vegetables. I gently toss everything so the ingredients are evenly distributed. This helps every bite taste balanced.
I pour the dressing over the pasta mixture and toss again until well coated. Then I fold in the feta and parsley gently to avoid breaking them up too much. I usually taste and adjust seasoning here.
I let the salad chill in the fridge for at least 30 minutes before serving. This step really helps the flavors meld together. Just before serving, I give it one last toss.