Heat a large skillet over medium-high. Add the ground beef and cook, breaking it up with a spoon, until evenly browned (about 6–8 minutes).

Drain excess fat, leaving about 3 tablespoons in the pan for flavor. Return the pan to the heat and sprinkle in the 2 tablespoons taco seasoning. Stir to coat the beef, then remove from heat and set aside to cool slightly.

Meanwhile, bring a pot of salted water to a boil and cook the rotini according to package directions until al dente. Drain and let the pasta steam-dry for a minute so it’s not too wet.

In a large bowl, combine the cooked beef, drained rotini, chopped yellow pepper, diced onion, halved grape tomatoes, shredded cheddar, and shredded iceberg lettuce.

Whisk the French dressing and sour cream together briefly, then pour over the salad. Toss gently to evenly coat.

Fold in the crushed Doritos, reserving about 1/2 cup for garnish. Taste and adjust seasoning (a pinch of salt or a squeeze of lime brightens it up).

Plate and sprinkle the reserved crushed Doritos on top. Add a dollop of sour cream if desired, then serve.