Remove cover from skillet and cook another 5 minutes. Cut butter into three pieces and lay each piece of butter in a different spot over the potatoes, allowing to melt. DO NOT STIR. Keep cooking until all liquid has evaporated and you hear a sizzling sound – that sound means that the potatoes are now starting to brown.Using something flat-bottomed (I use a tamper but anything flat-bottomed will do), gently press down on each potato to flatten gently (it’s okay if they split, you want to gently “pop” them). Now just leave them alone to brown – no stirring – for another 5 minutes or so, checking the bottoms occasionally.