Preheat your pellet smoker to 350°F.
In a mixing bowl, combine the ground beef with 2 tsp of BBQ seasoning. Mix well and form into 4 equal-sized burger patties.
Brush each patty with olive oil to prevent sticking and place them on the smoker.
Smoke the burger patties for 20-25 minutes or until they reach an internal temperature of 160°F.
While the burgers are cooking, melt the butter in a small saucepan over low heat. Add the chocolate chips and stir until melted and smooth.
When the burgers are almost done, place a slice of sharp cheese on each patty and let it melt.
Toast the burger buns on the smoker for a minute or two until they are lightly crispy.
To assemble the burgers, spread a tablespoon of horseradish sauce on the bottom bun. Add a slice of red onion, a few slices of pickles, and the smoked cheeseburger patty.
Drizzle the melted chocolate sauce over the patty, then add the top bun.
Serve and enjoy your delicious smoked chocolate burger!