I start by melting the butter in my pot over medium heat, then adding the onion and letting it cook until it turns soft and translucent. Next, I stir in the garlic and diced jalapeños, cooking for another two to three minutes until everything smells fragrant. This step builds the flavor foundation for the entire soup, so I never rush it.
Once the vegetables are softened, I sprinkle in the flour and stir constantly for about a minute so it cooks out its raw taste. This little roux is what gives the soup its classic thick, spoon-coating texture later on. I keep the heat at medium so the flour doesn't scorch or turn dark.
I slowly pour in the chicken broth while whisking continuously to avoid any lumps from forming. I bring the mixture up to a gentle simmer and let it cook for about ten minutes so the flavors meld together. This is the point where the soup really starts smelling incredible in my kitchen.
Next, I lower the heat and pour in the heavy cream along with the smoked paprika and cumin. I let it warm through gently, making sure it never comes to a hard boil, since cream can separate if it gets too hot too fast. This step turns the broth into something luxuriously creamy.
I add the freshly grated cheddar a handful at a time, stirring after each addition until fully melted before adding more. Going slow here keeps the cheese from clumping or turning grainy, which is a mistake I made the first time I ever tried this. Once all the cheese is incorporated, the soup turns thick, glossy, and irresistible.
Finally, I stir in the lime juice, taste for salt and pepper, and adjust as needed before ladling it into bowls. A squeeze of lime at the very end makes such a noticeable difference in balancing the richness. I usually let it rest for a minute or two off the heat before serving so it thickens slightly more.