Cream the butter with the brown sugar until light and fluffy. Beat in the oats and vanilla.
Add the flour and the condensed milk, a little of each at a time. You will not need all of the condensed milk-just enough to hold it all together. Leave over a little bit.
Stir in the chips, pb cups and white chocolate disks)
Press dough into a 9x9 square baking pan lined with nonstick foil.
Chill 3 hours.
Cut into squares!