Cut ham in at least 1 inch slices (chunks). Lay single layer into cake pan or roaster.
Mix mustard and brown sugar to make a paste. (consistency of honey) Drop by spoonfuls onto the ham slices. (put at least spoonful on each slice) If spread is to thick, add more mustard. Spread it around a bit on ham. However, don't spend alot of time on this, as it melts and covers the slices fine.
Add regular milk to pan until it comes up to middle of ham slice. (about 1/2-3/4 in, depending on how thick your ham is) Can use whole milk or 2%.
cover with foil and bake in 350 degree oven for app. 50 min. Again, it depends on how thick your ham is sliced.
When it's time to serve, spoon juice over baked potato and enjoy!