Preheat the oven to 425°F and line a large baking sheet with parchment paper.

In a large bowl, mix together the ground beef, eggs, minced onion, chopped cilantro, diced serrano pepper, grated garlic, cumin, allspice, kosher salt, black pepper, and a dash of cayenne pepper until well combined.

Form the mixture into two-inch meatballs and place them on the prepared baking sheet. Bake in the preheated oven for 10 minutes.

While the meatballs are baking, pour the beef broth and Mexican-style tomato sauce into a large frying pan and bring to a boil. Add the sliced zucchini and reduce the heat to a simmer, cooking uncovered.

After the meatballs have baked, transfer them to the frying pan with the sauce and zucchini. Let them simmer together for an additional 10 minutes.

Serve the meatballs and sauce in bowls, garnished with crumbled queso fresco and additional chopped cilantro.