Preheat oven to 375
Place beer can roaster on a pie tin, then open the can of beer, pour off about 1/4 th cup of the beer and place the can in the roaster.
Place the cleaned chicken on the roaster (the tip of legs will be pointing downwards) Place the onion in the cavity at the top of the chicken.
Rub the entire chicken in olive oil. Then use the Essence as a rub, and rub it all over the chicken.
And that's it. Bake for about an hour depending on the size of the chicken. If using one of those oven popper gadgets, bake it about 10 minutes more after the popper pops up.
This is one of my favorite ways to eat chicken, and I've done it with a small turkey also.
If you want to use a grill outside, you will have to add coals every so often to keep the temp up.