Broil poblano peppers until blackened. Place in a plastic bag until cooled enough to handle. Remove the skin, stems and seeds and chop.
Make the sour cream sauce first. Cook the poblanos, onions and garlic in a skillet until the onions soften.
Add the butter to the skillet and allow to melt. Whisk in the flour. Continue to whisk for two to three minutes. Whisk in the stock until smooth. Bring to a simmer and cook until thickens.
Whisk in sour cream and spices until smooth. Add to a blender and process until smooth. Pour in 1 cup of sauce on the bottom of the baking dish. Set the rest aside.
Add enough oil to cover the bottom of a clean skillet and heat over medium-high heat until shimmering. Place a corn tortilla in the oil and cook for 30 seconds. Flip and cook for another 30 seconds.
While the corn tortilla is still warm, add cheese and poblanos in the center of the tortilla. Fold each side of the tortilla and place seam-side down in the baking pan.
Pour the remaining sour cream sauce on top of the enchiladas. Sprinkle cheese on top and bake. Allow the enchiladas to rest before serving.