This green chili sauce from Blue Corn Harvest in Georgetown, TX pairs well with tacos, enchiladas, tamales, burritos and more. Anaheim peppers give a mild, sweet heat to this sauce. If you want to rev up the heat, toss in jalapeño or two. You can substitute Hatch green chili peppers or poblano peppers for the Anaheims.
Preheat your oven’s broiler. Line a rimmed baking sheet with foil and place the Anaheim peppers on the foil. Put the pan under the broiler and broil until the skin is mostly black. Remove the pan, flip the chilis and repeat. The charring process will take about 10 to 15 minutes.
Remove the chilis from the oven and immediately put them into a large resealable plastic bag and set aside for 15 to 20 minutes (this steaming process will loosen the skin on the peppers). Remove the chilis and carefully peel off the skin off each pepper. Slice lengthwise and scrape out the seeds with a spoon.
In a blender, puree the peppers with the chicken base and 2 cups of water. Strain through a fine mesh sieve set over a medium bowl.
In a large pot, heat the oil until shimmering. Add onion and cook over moderate heat, stirring occasionally, until translucent, 3 to 4 minutes.
Whisk in the flour and garlic and continue cooking and whisking for 3 minutes.
Reduce the heat to low, add the pureed chilies and continue cooking, stirring occasionally, until thickened, about 8 minutes.
Add the baking soda and cook for 2 minutes more. Season to taste with salt and white pepper.