Bring a large pot of water to a boil with a large pinch of salt. Halve, peel, and dice the onion. Peel and finely chop the carrot. Strip the thyme leaves off the sprig. Mince or grate the garlic. Core, seed, and remove the white veins from the poblano, then thinly slice. HINT: If you have a food processor, you can use it to chop the carrot and onion! Just roughly chop them before adding to the bowl.

Heat 1 tablespoon olive oil in a tall-sided pan over medium heat. Add the beef and season with salt and pepper. Cook for 6-8 minutes, breaking up the pieces, until golden brown. Set aside.

In the same pan, cook the poblanos over medium-high heat, adding another teaspoon olive oil if necessary. Cook, tossing, for about 2 minutes or until slightly blistered. Add the garlic and cook for 30 seconds, until fragrant. Season with salt and pepper. Set aside with the ground beef.

In the same pan, heat another teaspoon olive oil. Add the onion, thyme, and carrot and season with salt and pepper. Cook over medium heat for about 5 minutes, until softened. Return the beef and poblanos to the pan and add the diced tomatoes. Let simmer for 10 minutes.

Meanwhile, add the pasta to the boiling water. Cook 9-10 minutes, until al dente. Drain and reserve 1/2 cup pasta water. Add pasta to the sauce along with a splash of pasta water and the sour cream. Toss to combine, then taste and season with salt and pepper.