Preheat oven to 350 degrees. Spray a 9" x 13" baking dish with non-stick cooking spray. Set aside.
In a medium bowl mix together all cowboy butter sauce ingredients and set aside.
In a medium skillet over medium high heat, break up ground beef and cook until no longer pink. Drain excess grease. Stir in diced onion until softened. Stir in garlic for 30 seconds. Stir in Worcestershire sauce, hamburger seasoning, salt & pepper. Turn off heat.
Place bottom portion of slider buns in prepared baking dish. Baste bottom buns with 1/2 of the cowboy butter sauce. Top with the hamburger mixture. Place jalapenos on top of hamburger. Top with crisp bacon, cheese, fried onions, then tops of slider buns.
Baste top of buns with remainder cowboy butter mixture.
Cover baking with non-stick foil and bake for 15 minutes. Remove foil and bake an additional 5-10 minutes until cheese has melted. Remove from oven and serve.