Bring a large pot of salted water to a boil. Add the broken spaghetti pieces and cook according to package instructions until al dente. Drain and set aside.
Preheat your oven according to the garlic knots package instructions. Bake the garlic knots as directed until golden brown and fluffy.
In a mixing bowl, combine the roasted garlic pasta sauce and basil pesto. Stir until well mixed.
Remove garlic knots from the oven and let cool slightly. Carefully cut each garlic knot in half, creating a top and bottom.
On the bottom half of each garlic knot, add a spoonful of spaghetti, drizzle with sauce mixture, top with shredded mozzarella cheese, and sprinkle parmesan cheese on top.
Place the top half of the garlic knot onto the cheese and spaghetti layer, pressing gently. Repeat for all sliders.
Mix melted butter with garlic powder and chopped parsley. Brush mixture over the tops of assembled sliders.
Place assembled sliders in the oven and bake for 10-15 minutes until cheese is melted and bubbly, and garlic knots are crispy.
Remove sliders from oven and let cool a few minutes before serving. Drizzle with additional sauce if desired and enjoy.