Trim and cut chicken into four equal pieces. Season with salt and pepper, then cook in a frying or grill pan until the internal temperature reaches 165°F (74°C).
Spread butter on cut sides of slider rolls and toast in the oven for 4 to 5 minutes.
Top each chicken piece with a slice of Brie and let it melt for 1 to 2 minutes.
Assemble sliders with chicken, spinach, apple slices and jam on the toasted rolls. Top with remaining rolls and serve.