Nothing original with my methods.
1. Make a quick stock on the boil with beer, onions, a pinch of brown sugar, a little bit of hot mustard. When it has some taste, season it with salt and pepper. Reduce the heat to a bare simmer. Pierce the brats (duh!). Poach the brats (and/or any type of sausage which will hold together). Finally, brown the brats in a pan.
FWIW, I prep sausage for the gill in the same way. Speaking of the grill, if you're doing a lot of sausage, as for a party, the stock may be repurposed as a sausage hot tub and used to keep the brats hot.
Alternatively, make a stock with something other than beer and onions. Wine works well. Any kind of stock, even a light court buillon is preferable to plain water.
2. This one is a little simpler, a little quicker, and works especially well for frozen sausage. Hey! Frozen happens especially if you make your own. Pierce the sausage as best you can. Put them in a COLD pan with a little bit of water - no more than a 1/4", cover the pan and bring the fire up to medium/low. Three things will happen at the same time: The water will be more or less completely absorbed and replaced with sausage drippings; the sausage will be completely defrosted; and the skin will have just barely begun to brown. Remove the cover, increase the heat and finish browning as usual in the drippings.