Mix together the ground chicken with 2-3 tablespoons of Ragú® sauce. Season with salt & pepper. Shape the chicken into heaping tablespoon sized balls.
Heat a large skillet over medium heat. Using your hands, flatten the balls into patties & then place in the skillet. Cook until slightly brown on one side and then flip & cook the other side until cooked through & no longer pink, about 5 minutes per side. Repeat for each patty. Alternately, you can grill the chicken over medium heat for about 5 minutes per side or until preferred doneness.
While the chicken is cooking, heat the olive oil in a large skillet over medium heat. Add the onions & mushrooms & cook until the onions are tender and have begun to caramelize - about 10 minutes or so. Alternately, you could also grill the onions & mushrooms if desired instead of sauteing.
To assemble the sliders - place one cooked chicken patty on top of the bottom roll of a slider. Top with a spoonful of onions & mushrooms. Then top with a spoonful of warmed Ragú® Old World Style® Traditional Sauce & cover with top bun.
Serve hot.