Recipe(tried): Taco Filling

Personally, I like spicy filling (my daughter in law is part Mexican and I love her food). But, my suggestion if you do not want spicy is:

Take some onions and carmelize in a pan with a small amount of olive oil and butter (I use half and half of each). Add some (about a pound or so) ground beef, salt and pepper and cook till ground beef all well done.
Add a can of stewed tomatoes (chopped up good) with the juice. Use a medium or large can depending on how much juice you want. Let the mixture simmer for about 15- 20 minutes. If you keep covered it will be moister than if you leave off cover- juice will absorb into meat and steam will evaporate.

Then use for tacos or whatever.

Hope this helps!!