Hearthpwn

This is a control deck built with the idea of contesting and controlling the game until your opponent is in top deck mode and you finish it off with a Lord Jaraxxus play onto an empty board or close to empty board.  Mal'ganis allows you to make riskier plays with Jarraxus and usually will end up with your opponent conceding if both are on board. 

Mulligan advice:  Watchers, golems and void walkers are nice no matter what you are facing.  Owls are worth keeping if you have watcher in hand or are worried about an undertaker assault. 

BGH and TBK are tech cards and can be replaced as needed. 

The deck plays out decently vs most decks.  You may run into some issues with face hunters and mages but less if you have Mal'ganis you can stall long enough usually to get him and Lord Jaraxxus out to stabilize for the win since at that point board is clear and they are counting on hero power to finish you or top decking a damage spell.

General Play tips:  Every creature you have is expendable your goal is to use them to trade favorably and keep the other side empty.  A turn 2(with coin) or turn 3 silenced watcher can control the board until turn 5 when you can play sludges.  Once beyond turn 6 your odds of winning increase with every turn against most decks.