Stir the cornstarch, chili powder, cumin, paprika, salt, garlic powder, onion powder, and cayenne together in a bowl. Store in a ziplock bag or airtight container until ready to use.
Will last 3-6 months.
Notes
Add more or less cayenne pepper according to your spice preference. Cayenne pepper is what will make things spicy. Feel free to omit if you want a mild spice.