Step 1

In a medium bowl, mash the beef with the baking soda and salt. Let sit for at least 15 minutes or up to 1 hour.

Step 2

Heat the oil in a large nonstick skillet over medium heat until hot and shimmering. Add the onion and cook, stirring occasionally, until softened, about 4 minutes. Add the garlic and cook 1 minute more. Do not brown. Add the beef, chili powder, cumin, coriander, paprika, oregano, and cayenne pepper and cook, stirring constantly and breaking meat up with a wooden spoon, until the beef is no longer pink, about 5 minutes. Add the tomato sauce, water, sugar, and lime juice; bring to a simmer. Reduce the heat to medium-low and cook, uncovered, stirring frequently and breaking up the meat, until the liquid has reduced and thickened (the mixture should not be completely dry), 10 to 15 minutes. Taste and adjust seasonings if necessary.

Step 3

Using a wide, shallow spoon, divide the filling evenly among the taco shells; place two or three tacos on individual plates. Serve immediately, passing the toppings separately.

Step 4

Note: Nutritional info does not include optional toppings.