I think peppers and onions are a must and cook well in the foil alongside the steak. Beyond that, it’s kind of dealer’s choice. Here are a few of my favs (all of which you will find at my table when I serve fajitas):

Avocado
Sour cream
Red salsa, green salsa or pico
Hot sauce
After seasoning the steak and vegetables, you might have some spice mix leftover. You can use it to sprinkle on the fajitas before serving or keep it in the pantry. The spice mix is great on tacos and keeps well for three months in an airtight container.

INGREDIENTS
Fajita Spice Mix:

1 teaspoon kosher salt
1/2 teaspoon black pepper
1/2 teaspoon garlic powder
1/2 teaspoon onion powder
1/2 teaspoon ground cumin
1/2 teaspoon chili powder
For the fajitas:

1 1/2 pounds steak, skirt, flank, or strip (no more than 1-inch thick)
1 large green pepper, sliced thin
1 large red pepper, sliced thin
1 medium sweet onion, sliced thin
4 teaspoons olive oil
10-12 medium flour tortillas
DAD ADD — Lime Cumin Sour Cream:

1 cup sour cream
1 lime, zest and juice
1/2 teaspoon ground cumin
Pinch of salt

I think peppers and onions are a must and cook well in the foil alongside the steak. Beyond that, it’s kind of dealer’s choice. Here are a few of my favs (all of which you will find at my table when I serve fajitas):

Avocado
Sour cream
Red salsa, green salsa or pico
Hot sauce
After seasoning the steak and vegetables, you might have some spice mix leftover. You can use it to sprinkle on the fajitas before serving or keep it in the pantry. The spice mix is great on tacos and keeps well for three months in an airtight container.

INGREDIENTS
Fajita Spice Mix:

1 teaspoon kosher salt
1/2 teaspoon black pepper
1/2 teaspoon garlic powder
1/2 teaspoon onion powder
1/2 teaspoon ground cumin
1/2 teaspoon chili powder
For the fajitas:

1 1/2 pounds steak, skirt, flank, or strip (no more than 1-inch thick)
1 large green pepper, sliced thin
1 large red pepper, sliced thin
1 medium sweet onion, sliced thin
4 teaspoons olive oil
10-12 medium flour tortillas
DAD ADD — Lime Cumin Sour Cream:

1 cup sour cream
1 lime, zest and juice
1/2 teaspoon ground cumin
Pinch of salt
To serve:

Avocado
Salsa
Hot sauce