Using a mandoline or food processor, slice the potatoes very thinly. Heat your oven to 325°F (162°C).

Heat a 12” (24cm) cast iron skillet on the stove. Add the olive oil and heat well. Add the onion and sauté until golden brown. Add the garlic and remove the pan from the heat. Season the mixture lightly with salt and pepper.

Arrange the sliced potatoes over the top of the onions, preferably in a circular pattern in the skillet. Season the top of the potatoes lightly with salt and pepper, but do not stir. Pour over the Mexican crema and spread evenly over the potatoes. Cover with aluminum foil and place the potatoes in the oven for 60-75 minutes.

Meanwhile, roast the chile poblano over an open flame on a gas stove.* Wrap the roasted chile in a clean kitchen towel, and then place the bundle in a paper bag. Allow the chile to sweat for 10-15 minutes. Remove the chile from the bundle, scrape away the blackened peel, cut away the top and remove the seeds. You may wish to rinse the prepared chile under running eater to remove any remaining charred skin and seeds. Slice the prepared chile into strips and set aside.

Remove the skillet from the oven. Switch the oven function to broil.  Carefully remove the aluminum foil. Arrange the prepared chiles evenly over the top of the potatoes. Sprinkle over the cheeses. Place the pan under the heated broiler for 3-5 minutes until the cheeses are melted and golden brown. Serve warm.