Step #1 Light a grill or preheat a cast-iron grill pan over low heat/flame for about 10 mins.
Step #2 In a small skillet, toast the cumin seeds over moderately high heat until lightly browned & fragrant, about 30 seconds.
Step #3 Transfer to a.
Step #4 mortar to cool; then, using a pestle, coarsely grind.
Step #5 Add the black pepper & garlic & lb to a paste.
Step #6 (Alternatively, using a chef’s knife, chop the cumin seeds as fine as you can & put them in a small bowl along with the black pepper.
Step #7 Mince the garlic & add it to the spices.
Step #8 ) Stir inches.
Step #9 the olive oil.
Step #10 Rub the cumin oil on the skirt steak & marinate for at least 10 mins or put in the fridge overnight.
Step #11 Roast the poblano chiles directly on the grill or over a gas flame, turning often, until blistered all over; do not overcook or the flesh will burn.
Step #12 Transfer the chiles to a paper bag & let steam for about 5 mins.
Step #13 Using a small knife, remove the skin, stems, & seeds.
Step #14 Cut the chiles into thin strips.
Step #15 In a small bowl, mix the chiles & sour cream.
Step #16 Spice up with salt.
Step #17 Spice up the skirt steak with salt & grill over a very hot fire or in the grill pan over high heat for about 2 1/2 mins per side for medium-rare.
Step #18 Transfer to a carving board to rest for about 5 mins.
Step #19 Using a very sharp knife, thinly slice the steak lengthwise against the grain.
Step #20 Warm the tortillas on the grill for a few seconds until pliable.
Step #21 Place the sour cream, tomatoes, onion, & avocado in bowls.
Step #22 Serve alongside the steak & tortillas & let each person assemble his own fajita.