In a large stockpot or Dutch oven, melt butter over medium heat.

Add onion, leek, red bell pepper, carrots, and celery. Season generously with salt and pepper.

Sauté about 5-10 minutes until veggies are tender and a fork pierces through the carrot slices easily.

Stir in flour.

Slowly add half-and-half a few tablespoons at a time and whisk until each addition is fully incorporated.

Reduce heat and allow sauce to thicken, about 5-10 minutes.

Stir in Pesto Red Potatoes.

Check seasoning. Add salt and pepper, to taste.

Ladle soup into bowls and garnish with bacon pieces, shredded parmesan cheese, and fresh basil, as desired.