1. Heat the Pot and Brown the Beef

Start by selecting a large heavy-bottomed pot, ideal for even heating and easy stirring during the one-pot process. Drizzle in 1 tablespoon of olive oil and set the pot over medium-high heat until the oil shimmers slightly, signaling it is ready for the ingredients. This initial high heat ensures quick searing for flavor development.

Add 1 pound of lean ground beef along with 1 diced onion and a small pinch of salt right away. The lean beef minimizes fat drainage, keeping the process streamlined. Use a wooden spoon to break up the beef into small crumbles as it cooks, allowing even browning and preventing large chunks that could lead to uneven cooking.

Cook this mixture for about 5 to 6 minutes, stirring occasionally. Watch for the beef to turn fully browned and the onions to soften and gain golden color, which builds a savory base. The aroma of sizzling beef and onions will fill your kitchen, promising a comforting meal ahead.

2. Add Garlic and Spices

Once the beef and onions look perfectly cooked with no pink remaining in the meat, stir in 2 minced cloves of garlic. Garlic adds a pungent depth but burns easily, so saute it for just 45 seconds to 1 minute while stirring constantly. This step releases its flavors without bitterness.

Sprinkle in 1 tablespoon of chili powder, 1 teaspoon of ground cumin, and 1 teaspoon of dried oregano. These spices form the chili profile, with chili powder providing mild heat, cumin offering earthiness, and oregano a herbal note. Stir vigorously for 30 seconds to toast the spices, enhancing their potency and infusing the meat mixture thoroughly.

Taste the mixture at this point and adjust seasoning with another pinch of salt if needed. The spices should bloom fragrantly, setting the stage for the liquids to absorb these bold flavors evenly.

3. Simmer the Chili Base

Pour in 2 cups of water, the 14-ounce can of diced tomatoes with chilis, and 1 cup of milk. The milk might seem unusual for chili, but it contributes creaminess akin to mac and cheese elements, balancing the tomatoes’ acidity. Stir everything together to combine.

Bring the mixture to a gentle boil over medium heat, then reduce to low for a simmer. Let it bubble softly for exactly 10 minutes, uncovered. This allows flavors to meld, tomatoes to break down slightly, and the sauce to thicken naturally. If the milk looks like it might separate initially, persist with the simmer; it emulsifies perfectly by the end.

After simmering, taste again for balance. Add a touch more chili powder for heat if desired, keeping it family-friendly as in the original recipe. The base now resembles a thickened chili, ready for pasta.

4. Cook the Pasta

Stir in 8 ounces of pasta shells or your preferred short-cut pasta directly into the simmering liquid. Short shapes like shells hold sauce well, trapping cheesy goodness in every bite. Push the pasta down to submerge it as much as possible, though it may seem scant on liquid; this ensures a thick, not soupy, final dish.

Cover the pot with a lid, lower heat to medium-low, and cook for another 10 minutes without stirring initially. The pasta absorbs the chili-infused liquid, cooking al dente while the sauce reduces. Check at 10 minutes; most liquid should be gone, and pasta tender.

Remove from heat once done. The pot now holds a cohesive chili-pasta blend, primed for creamy finishing touches.

5. Finish with Creaminess

Stir in 1/2 cup of sour cream first, which introduces tanginess and further creaminess, mimicking the richness of stovetop mac and cheese. Mix until fully incorporated, smoothing out any lumps for a velvety texture.

Gradually add 2 cups of shredded cheddar cheese in handfuls, stirring after each addition. A mix of white and yellow cheddar works best for color and melt. Let residual heat melt the cheese completely, creating stretchy, gooey strands. Avoid high heat here to prevent separation.

Give one final stir to ensure even distribution. The dish transforms into a luscious, cohesive chili mac and cheese, with pasta coated in spicy, cheesy sauce.

6. Serve and Garnish

Spoon into bowls immediately for optimal creaminess. Top each serving with chopped green onions for fresh crunch and color, echoing traditional chili garnishes. Drizzle hot sauce for personalized heat.