Pour 3 cups cold water into a medium bowl; ADD the remaining seasoning mix ingredients and whisk mixture well until dry ingredients are thoroughly dissolved; set aside.
Brown the ground taco beef in a skillet over medium-high heat while stirring without overcooking (drain ground beef if necessary); Pour the blended seasoning mix into the browned taco beef in skillet and raise heat to high and boil mixture for one minute, stirring.
Reduce heat to medium and COOK mixture, stirring occasionally, until very little liquid remains and ground beef is moist yet not soggy.
Cover beef mixture and reduce heat to low; simmer for 5-7 minutes to steam and tenderize meat, and for flavors to infuse fully.
Spoon beef into corn tortillas and serve with diced tomatoes, shredded cheese and lettuce, topped with sour cream.Makes 8 to 10 Source: