When cooking a meal that includes browned hamburger meat (like tacos or casseroles) try this trick:
Get out a large, deep bowl. Find a somewhat flat, small bowl that will fit nicely in the bottom of the larger bowl, and place it in the bowl upside down, ensuring that the small bowl is well fitted to the sides of the larger bowl.
Pour in the browned hamburger meat and place in a warmed oven for 10-15 minutes. The grease in the hamburger meat will slowly drain, running under the bowl and into the space created under it.
You will be amazed at the amound of fat that drains from the hamburger!
Scoop out the hamburger, making sure that you do not disturb the small bowl (and the grease) that rests in the bottom and proceed with your recipe.