Before starting the beef, measure out all the spices into a bowl and set aside. This makes it easy to pour into the beef mixture when needed.
In a large saucepan or pot, add olive oil and heat on medium high heat. Add finely chopped onions. Stir to coat in oil, then cover and heat until soft.
Once soft, add garlic and ginger into pot. Stir for 1-2 minutes until garlic and ginger are fragrant.
Then add beef to pan. Sautee beef until cooked through. Then add all the spices and mix well.
Continue to sautee until beef is slightly crispy on the edges - this gives it a lot of flavor in the tacos. Strain beef and set aside. (Note, if you'd like your beef spicy but some in your group don't, you can set aside half the beef without red pepper flakes, then add some red pepper flakes to the other half - we really love the flavor of the spice, but it's too much for our kids. This is a good way to compromise.)