Beer Bratwursts with Onions and Grilled Cabbage

avocado oil

large yellow onion, cut in half and thinly sliced

kosher salt

black pepper

bratwurst sausages links, uncooked ((about 2 pounds))

bottle [11.2 ounces] beer ((I use Hoegaarden, biere blanche))

head green cabbage, cut into wedges about 1/2 inch thick ((I leave on the core to keep it together while grilling, you can eat around it))

head purple cabbage, cut into wedges about 1/2 inch thick ((see above))

avocado oil

kosher salt

black pepper

fresh lemon juice ((about 1 lemon))

chives, chopped fine

grainy mustard

dijon mustard

lemon, cut into wedges

sauerkraut (optional)