Soak the Great Northern beans in a large bowl with water and a pinch of kosher salt for at least 8 hours or overnight. Drain and set aside.

Preheat the oven’s broiler to high. Broil the poblano chiles on a baking sheet for 8–10 minutes, until blackened. Transfer to a sealed bag to steam for 10 minutes.

In a pot, bring water to a gentle boil, add chicken thighs and 1 teaspoon of kosher salt, simmer for about 20 minutes. Remove chicken and shred it.

In a large pot, melt 2 tablespoons of unsalted butter over medium heat. Add diced onion and chopped jalapeños, cooking for 5–7 minutes. Add minced garlic last.

Add soaked beans, peeled and diced poblano chiles, ground cumin, chili powder, and cayenne pepper. Pour in chicken broth to cover, and bring to a boil.

Reduce heat to low, partially cover the pot with a lid, and simmer for about 1.5 hours, stirring occasionally, until beans are tender.

Stir in the shredded chicken and continue cooking uncovered for an additional 30 minutes.

Mix masa harina with a bit of reserved broth until smooth, stir into chili for thickness and creaminess. Add thinly sliced poblano strips.

Taste and adjust seasoning, then serve hot garnished with sour cream and lime wedges.