Heat a skillet over medium-high heat. Add the fat from the ham and render. When the fat is rendered, add the ham steaks and pan-fry until golden brown on both sides. Remove the ham from the pan and set aside on a plate and keep warm. To the pan, add the coffee and water and stir with a wooden spoon, scraping up any browned bits from the bottom of the pan. Add the butter and the bouillon cube and stir to incorporate. Serve the gravy over the ham steaks on grits.