Cook the bacon in a skillet until brown. Remove the bacon and drain the fat, reserving 2 tablespoons of the grease inside the skillet. Add the onions to the bacon grease and cook until translucent over medium heat. Add garlic, jalapeno and collards and cook for an additional 3 minutes. Combine cream cheese, Parmesan cheese, mayo, salt and pepper in a bowl until mixed well. Add the collard mixture to the bowl and add the sharp white cheddar. Combine well. Pour into a casserole dish. Top with yellow cheddar cheese. Bake on 350 degrees until bubbly and slightly brown on top. Sprinkle chopped bacon and chopped scallions on top right before serving. Serve with crispy cornbread, fried cornbread, toast wedges, crackers, corn chips or tortilla chips.