In a skillet, melt butter over medium-low heat. Add sliced sweet onions and cook, stirring occasionally, for about 25-30 minutes until they turn golden brown and fragrant.

In a bowl, mix ground chicken with Worcestershire sauce, onion powder, garlic powder, and half of the caramelized onions. Stir until well combined, then add to the skillet and cook over medium-high heat until no longer pink, about 5-7 minutes.

While the chicken is cooking, preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

Place slider buns on the prepared baking sheet. Layer each bun with the chicken mixture, a generous amount of remaining caramelized onions, and a slice of gruyere cheese. Top with the bun lids.

Melt any remaining butter and brush it over the tops of the buns. Add a sprinkle of sesame seeds and fresh thyme for extra flavor.

Place the sliders in the preheated oven and bake for about 20 minutes or until the cheese is bubbly and the tops are golden brown.

Allow the sliders to cool for a minute before serving warm for that perfect bite.