In a large bowl or container with a lid, add water, sugar, soy sauce, salt, and olive oil.
Mix well and stir to dissolve.
Add chicken and cover with ice, place lid or plastic wrap over chicken. Place in refrigerator or keep adding ice to keep chicken cold as it brines.
Brine chicken for at least 6 hours and up to overnight.
Preheat oven to 350 degrees.
Remove chicken from brine and pat dry thoroughly.
Mix butter and remaining herbs and spices and rub generously all over outside and inside of chicken.
If injecting chicken with cajun butter, melt butter and spices and inject throughout chicken.
Stuff onion, lemon, and garlic into chicken cavity. Truss if desired.
Place chicken in dutch oven and place stock in bottom. Cover with lid.
Roast chicken at 350 degrees for about an hour with lid on. Baste occasionally with chicken stock.
Remove lid from dutch oven and cook the rest of the 30 (+/-) minutes until an internal temperature reads 160 degrees.
If chicken skin is not crisp enough, place under broiler the last 5-10 minutes on high (watching carefully to prevent burning) until skin gets crispy and golden brown.
Remove chicken from dutch oven and place on cooling rack, tent with foil and let rest for 15 minutes to lock in the juices.
Carve and serve - enjoy!