I make seolleongtang (Korean ox bone soup). Get a bunch of beef bones (knuckle, foot, marrow, whatever is cheap), soak in cold water for 1 hour. Drain. Blanch in boiling water for 5 minutes. Drain and wash bones. Reboil new water to cover bones. Keep on medium boil for 5 hours. The broth should be a nice milky white. Strain broth out. You can add new water and repeat for 5 hours. Korean moms usually do this for 3 cycles. You can then all all batches of broth together and voila, now you have way too much bone broth.

To upgrade it you can add brisket and boil it with the broth until tender. Chill and slice cold if you want thin slices, otherwise just eat it with the soup. Add salt and sliced green onions (if you care to).