01 -
Preheat oven to 190°C. Halve poblano peppers lengthwise and remove seeds and membranes. Place peppers and chopped onions on a baking sheet. Drizzle with olive oil and season lightly with salt and black pepper. Toss to coat evenly and arrange peppers skin side up. Roast for 30 minutes.
02 -
Transfer roasted peppers to a plastic bag or cover in a bowl with plastic wrap to steam. Allow to rest until cool enough to handle, then peel away and discard the outer skins.
03 -
In a medium skillet over medium-high heat, melt butter. Add flour and whisk continuously, cooking until the mixture turns lightly golden, about 2–3 minutes. Gradually whisk in chicken broth and continue cooking for 5–10 minutes until the mixture is slightly thickened.
04 -
Transfer the roux mixture to a blender or food processor. Add peeled poblanos, roasted onions, sour cream, garlic cloves, cumin, and salt. Blend until smooth. Taste and adjust seasoning with additional salt and black pepper as required.