Melt butter in a large skillet and add onion and cook for 1 minute.
Add mushrooms, and cook until mushrooms begin to soften.
Add garlic and jalapeño and cook for about 5 minutes.
Remove skillet from heat and drizzle with lime juice and sprinkle chopped cilantro and combine.
Arepas:
Add milk, salt, cream cheese, and 4 tablespoons of butter to a mixing bowl and whisk until creamy.
Add flour and cheese. Hand mix until well combined.
Divide the dough into eight balls.
Form each ball into a hockey puck shape.
Melt 2 tablespoons butter in a 12-inch cast iron or non-stick skillet over medium heat.
Add the arepas to the pan and let the arepas cook for about 5 to 6 minutes on each side until they are golden brown.
Using a spatula, remove the arepas, and split each arepa in half and fill with the mushroom mixture and sprinkle with crumbled queso fresco. Serve warm.
Notes
Once these arepas are cooked they can be filled with virtually anything, so feel free to add another filling.