In a medium sautรฉ pan over medium heat, melt butter. Place onions in a pan and sautรฉ until soft and begin to caramelize.
Add ham and sautรฉ until it begins to brown. Add cream cheese and stir until soft and begins to melt. Turn heat down to low, add remaining cheeses. Continue stirring until everything is well combined.
Pour into ovenproof baking dish (8×8 dish) and bake for 20 minutes until cheeses are fully melted.
Stir in scallion and serve with your favorite crackers, chips, breads or vegetables.