Ah, I have one of these, great bit of kit!
Right, American, you have 4 options:
1. You get one of the standard plug-in Brauns; you can adapt a household socket from NA to EU standard (flat pin—>round pin or British), but it will run very weedily, as the voltage (and so the power) will be half the intended. If you were to do this, you may as well just change the plug-top permanently. No point having a half-powered Braun really though, is there?
2. To change the actual voltage, you can buy a transformer to plug in in your kitchen (like @thorninmud says), but that is fucking ridiculous.
3. You can wire a new circuit or spur for a 220V supply to your kitchen (as @CWOTUS says). US houses need ‘special’ separate circuits for 220V supplies, but this is routine and possible in all households. You have two-phase supplies in US household, I think you use a different sort of plug top, wire in twin-and-earth, with the conductors connected across the phases. I’ve never done any work in America though, so I can’t help you any further here, you’d have to see an electrician, which would be pretty dear for what you’re getting.
4. Buy the ‘wireless’ one. It has a battery, which will always provide the same power to your tool, so you will definitely get full power. The power supply for the wireless model runs through a dual-voltage (110~240V) battery charger, which will work perfectly fine with a standard 120V socket in your American home. You will still need to change the plug-top, or use a plug-top adaptor (standard travel-adaptor, like @Skaggfacemutt says).
Personally, I’d recommend the wireless option, just change the plug-top. Cheaper than getting a sparky in, and much less ridiculous than having a 1000W transformer sitting on your worktop.