In the same skillet you used for the cube steak, melt the butter.
Once melted, whisk in the flour, stirring consistently until well blended. Allow the mixture to simmer for about 30 seconds.
Slowly pour in the beef broth, whisking until blended. Bring to a low boil for 2-3 minutes. Add in the minced onion, salt, and pepper. Stir, then lower the heat to simmer for another 5-10 minutes.
Pour the gravy over the steaks in the Instant Pot.