Begin by heating the vegetable oil in a medium pot over medium heat. Add the dry shell pasta and toast it, stirring frequently, until it reaches a golden-brown color. This step gives the soup a warm, nutty flavor and brings depth to the overall dish—much like the toasting in traditional soaps de fideo.
Step 2: Blend the Tomato Base
While the pasta is toasting, blend the tomatoes, garlic, and onion until smooth. This fresh tomato mixture forms the foundation of the broth and is what distinguishes this as a true mexican soup recipe, rather than just plain pasta in broth.
Step 3: Cook the Tomato Mixture
Once the pasta is toasted, pour in the tomato mixture carefully (it might splatter a bit). Stir and cook it for a few minutes until the tomato sauce slightly darkens and the raw tomato smell disappears. This is when the kitchen really starts to smell like childhood memories.
Step 4: Add the Broth and Simmer
Pour in the chicken or vegetable broth and bring everything to a boil. Then reduce the heat and simmer for about 15-20 minutes, or until the shell pasta is tender and the broth has thickened slightly. Stir occasionally to prevent sticking.
Step 5: Season and Serve
Taste and adjust the seasoning with salt and pepper. Ladle the soup into bowls and top with avocado, queso fresco, cilantro, or a squeeze of lime.