I made some brats last year, started off using the prepackaged mixes you can buy and wasnt crazy about the flavor they had, so I tried my own ingredients and came up with a relatively simple recipe that had awesome taste.

10 lbs ground venison
5 lbs ground bacon end pieces {cheap ones in the box, mostly fat}
1 High Mountain Brat seasoning kit with casings
1 large red onion
2 cloves garlic
1 bag cheddar cheese curds

Grind the pork and venison and mix together in large bowl, grind the onion and garlic and mix it , the cheese curds,and the High Mountain seasoningin with the meatthoroughly by hand, , let sit overnight.Mix it all by hand again run it back through grinder into Brat size sausage casing twisting them off every 6 inches or so.