2 Tbsp. extra-virgin olive oi
l ½ medium red onion, chopped
2 garlic cloves, chopped
1 Tbsp. achiote paste or tomato paste 8 ancho chiles, stemmed, seeded
1 chipotle chile in adobo, chopped (or 1 Tbsp. adobo sauce to keep things mild)
3 cups low-sodium chicken stock
1 tsp. ground cumin
2 tsp. kosher salt, plus more
1 rotisserie chicken, meat pulled from bones and shredded
Heat oil in a large saucepan over medium-high until shimmering. Cook garlic and half of onion, stirring occasionally, until tender and beginning to brown, 6–8 minutes. Stir in achiote paste and cook, stirring occasionally, until brick red, about 1 minute. Add ancho chiles, chipotle chile, stock, cumin, and 2 tsp. salt and bring to a boil. Cover, remove from heat, and let sit until chiles are very soft, about 30 minutes. Transfer chile mixture to a blender and purée until smooth. Return to saucepan, stir in chicken, and bring to a simmer over medium-low heat; season with salt.