Rajas con crema, or poblano peppers in cream, is a traditional Mexican dish that's served as a side for tacos. According to chef Patricio Sandoval of Mercadito Restaurants, it's best served in warmed tortillas.
Roast the peppers on top of a burner until they're black on all sides. Remove and place in a plastic bag for 10 minutes to "sweat." Peel the thin layer off, remove seeds and veins, and julienne.
In a medium saucepan, heat up the oil, add the onions, and sweat them until translucent. Season with salt. Add the julienned poblanos and sweat for 3-5 minutes. Season with salt again. Remove from heat and add 2 cups of crema fresca.