Drain and rinse 1 can of kidney beans. Dump onto a cutting board and roughly chop.
Set a large soup pot on the stove over medium-high heat. Add 2 tablespoons butter. When it’s melted and just starting to smell nutty, add the chopped beans. Spread into an even layer, then don’t touch! Fry for about 6 minutes until crispy. Transfer to a plate and sprinkle with a pinch of salt.
Immediately add another 2 tablespoons butter to the pot. When it’s melted, add the chili powder. Stir-fry for about 30 seconds until it’s very fragrant—but not longer, or else it will burn. Add the onions, poblanos, and a big pinch of salt. Stir to completely coat the vegetables in the chili butter. Cook, stirring every so often, for about 15 minutes until the vegetables are soft; lower the heat and add a small splash of water as needed to prevent any burning.
Meanwhile, rinse and drain the second can of beans.
When the vegetables are soft, add the canned tomatoes and their juices. Smash with a spoon to roughly break up the tomatoes. Add the water, chopped-fried beans, whole beans, remaining 2 tablespoons butter, and another big pinch of salt. Adjust the heat to bring to a simmer.
Simmer for about 15 minutes until the flavors are full and delicious to you. Taste and adjust the salt again if necessary.
Emma is the food editor at Food52. Before this, she worked a lot of odd jobs, all at the same time. Think: stir-frying noodles "on the fly," baking dozens of pastries at 3 a.m., reviewing restaurants, and writing articles about everything from how to use leftover mashed potatoes to the history of pies in North Carolina. Now she lives in Maplewood, New Jersey with her husband and their cat, Butter. Stay tuned every Tuesday for Emma's cooking column, Big Little Recipes, all about big flavor and little ingredient lists. And see what she's up to on Instagram at @emmalaperruque.