Heat a skillet to medium high and brown onion and ground beef, until cooked fully through. Add salt and pepper to taste.
Drain off access fat and return to heat, stirring in garlic and taco seasoning, cooking for 3 to 5 minutes.
Place taco shells in your Taco Tender and fill with the beef mixture.
Top with shredded lettuce, sour cream, salsa, and jalapenos.