The overhead press is a great exercise to develop the shoulders while increasing your vertical pushing strength. A strong overhead press will also require other stabilizing muscles to activate so you'll be working towards a strong posture and core while performing this movement.
A unilateral overhead press (one side only) will engage the core even more. I'll show how
in this tutorial as well. Seriously, try one arm only and no doubt you'll see exactly what I'm talking about!
Who knows? You might find that the heavy 6 quart slow cooker is a piece of cake to take out of that very top kitchen cabinet if you keep at it! I've heard just about every instance where new found strength is recognized! And no one is complaining about those gains!