Step 1

Preheat the oven to 350 F. Add the potatoes and 3 tablespoons of salt to a large pot and add enough water to cover.

Step 2

Bring to a boil and cook until tender, then drain and transfer to a large mixing bowl.

Step 3

Add 1 tablespoon of salt and, using a spoon or spatula, smash the potatoes.

Step 4

Meanwhile, char the poblanos over an open flame of the stovetop, using tongs to rotate them to get a nice even char.

Step 5

Transfer to a bowl and cover; let sit for 10 minutes.

Step 6

Using a paper towel, scrape the skin off the poblano peppers (do not rinse), then carefully remove the stems and seeds.

Step 7

Cut four of the peppers into thin strips and reserve.

Step 8

Place the remaining 2 peppers into a blender, add the serrano, parsley, cream cheese and heavy cream, and blend just until smooth; do not overblend.

Step 9

In a large skillet, melt the butter.

Step 10

Add the onions, garlic and 1 tablespoon of salt and saute over medium heat until softened.

Step 11

Add the poblano-cream cheese sauce and poblano strips, and mix to combine.

Step 12

Bring to a simmer and cook for 1 minute.

Step 13

Pour the contents of the skillet over the potatoes and mix to combine; season with salt, to taste.

Step 14

Pour into a casserole dish, sprinkle the cheese evenly over the top and bake until warmed through and the cheese is golden and crispy.