Slice sirloin/tenderloin into 1/4"to 1/2" cubes (pre-partial freezing meat makes for easier slicing). Melt butter over medium-high heat and brown meat, uncovered.

Reduce heat to low and add all remaining ingredients except beans. Cover and simmer for 2-3 hours, stirring occasionally.

15 minutes before done, add beans and stir, replace cover.

Best served over fritos, tortilla chips, or crackers, with a generous helping of shredded cheddar cheese. Also good atop hot dogs, baked potatoes, and cooked rice or pasta.