METHOD TO PREPARE

In a wide skillet, melt butter over medium heat. Add olive oil.
When the butter foams, throw in the sliced onions.
Add salt.
Stir to coat the onions and let it continue to cook till it is caramalized and soft. Stir every 5 - 10 minutes during the cooking process to prevent the onions from burning. This should take about 20 minutes.
When it is done, add in red wine vinegar, red pepper flakes and black pepper. Coninue to cook for another 3-5 minutes.
While the onion is cooking, prepare the garlic butter. Melt 2 tablespoons of butter in a small bowl, add garlic and chopped herbs.
Slice the Slider buns horizontally into half.
Place the bottom half on a parchment line baking tray.
Brush some garlic butter on the slider bun.
Spread the carmalized onion evenly on the bun.
Spread shredded paneer and top with shredded mozzarella.
Place the top half of the slider bun.
Brush with remain garlic butter.
Cover the whole bun with foil and cook for 20 - 25 minutes, till the cheese is nice and melty.
Take it off the oven remove the foil and let it cool for a 5 minutes and then serve hot.