Slice the the onions and bell peppers. Heat 1 tablespoon olive oil in a 12" skillet over medium high heat. Add the onions and allow to cook for about 5 minutes, or until softened and fragrant. Add the bell peppers and sprinkle with the reserved 1 1/2 teaspoons of fajita seasonings.
Reserve 1 1/2 teaspoons for the bell peppers. In a medium bowl, combine 2 tablespoons of olive oil, chopped cilantro, lime juice, mustard and 5 teaspoons of the fajita seasonings. Reserve 1 tablespoon of the steak marinade for drizzling on the steak at the end. Pour remainder of the steak marinade into a large zip-top bag along with the steak.
Low Carb Steak Fajitas are tender, juicy and full of flavor! Best of all, this easy recipe comes together super quick and perfect for busy weeknights. Marinated in a homemade fajita spice blend and cilantro lime marinade. Fajitas happen a lot around here. Chicken, Shrimp and these Low Carb Steak Fajitas. They are actually really simple to make.
For the marinade: In a blender, combine the olive oil, chili powder, Worcestershire, cumin, red pepper flakes, garlic and lime juice. Next add the sugar, salt and pepper and blend the marinade until it's totally combined and smooth. For the meat: Place the chicken and beef in separate 2-quart baking dishes or large resealable plastic storage bags.