First, fire-roast your poblano pepper by blackening the skin all over by holding it over a direct flame (like a gas burner on a stove top, or a kitchen torch) or by placing it under the broiler of your oven.

Turn the pepper often so that it blackens evenly.

Immediately seal it in an airtight container and let it sweat for about 10 minutes.

Scrape the skin off the pepper with the back of a knife and then dice the pepper.

While the pepper is sweating, peel and dice the sweet potatoes into 1/4 - 1/2 inch pieces.

In a heavy-bottomed skillet heat the oil with the minced garlic for one minute.

Add the sweet potatoes, season with the ground cumin and chili powder, and saute for about 5 minutes. If at any time sweet potatoes start to stick to the pan add a little vegetable broth to keep things moist.

Add the diced poblano and the black beans and continue to saute until the sweet potatoes are softened.

Add another 1/4 cup of vegetable broth to de-glaze the pan.

Serve in corn tortillas and sprinkle with cotija cheese. Sour cream with a little adobo sauce (from a can of gluten free chipotle peppers.) or even chipotle mayo, if you want to limit the dairy.