3 pounds red (or Yukon Gold) potatoes
4 tablespoons (¼ cup) butter
1 small white onion, peeled and diced (about 1 cup)
1 small green bell pepper, cored and diced (about 1 cup)
1 small red bell pepper, cored and diced (about 1 cup)
1 jalapeno, seeded and finely diced
2 (4-ounce) cans Old El Paso chopped green chiles
1 ½ cups shredded sharp cheddar cheese
¾ cup milk, warmed (add more if needed)
1 teaspoon salt, or more to taste
½ teaspoon black pepper, or more to taste
(optional toppings: thinly-sliced green onions, extra shredded sharp cheddar cheese)
