Cook the onion and sausage in a nonstick frying pan for about 10 minutes until lightly browned. Remove a few spoonfuls of the sausage and reserve to use as a garnish.

Meanwhile, mix the cornstarch with the milk in a bowl. Mix until all the starch is dissolved.

Pour the milk mixture into the sausage mixture and bring to a simmer. When it comes to a simmer you will notice it thicken up.

Remove from heat and stir in the cheeses. They will mostly melt into the sauce.

Pour the mixture into a small baking dish or cast iron skillet.

Cover and chill or cook immediately. If cooking right away, bake at 350 for 10 minutes. If cooking from cold, bake at 350 for 30 minutes.

Garnish with the reserved sausage, the salsa, jalapenos, and cilantro. Serve with pita chips.