You will need a Dutch oven or something similar, a mortar (a food processor should be fine too), a grater and a chef's knife.
I bought a organic corn-feed chicken which was quite heavy (2.5kg) but any will do. The lemons should be organic since you will use the peel.
Add the rosemary and lemon zest from 1 of the lemons to the mortar. If you don't have a zester try to cut it very thin.
Add a pinch of the sea salt. Be careful it's easy to overdose with the coarse salt. Take your pestill and smash it up.
It should reach a creamy consistency. Now ad the juice of the zested lemon and olive oil to it. The amount of oil depends on the initial amount of rosemary.
Now take the second lemon and boil it for 5-10 minutes. The water will turn a little yellow.
While the lemon boils peel and cut the carrots in big pieces.
Do the same with the onions.
And the potatoes.
You can put all the veggies at the bottom layer into the Dutch oven. Add a generous amount of olive oil and mix it up.
Rub the rosemary-olive oil-lemon mixture on the chicken (outside AND inside).
Take the lemon out of the boiling water and stab it multiple times with a knife. CAREFUL hot lemon juice will squirt out!
Put the hot lemon INTO the chicken's cavity. If you have a large chicken feel free to add further filling.
Using a boiled lemon decreases the roasting time and creates an even temperature throughout the chicken. Perhaps more importantly the boiling releases the juices, adding to flavor!
You can close it up using a rosemary twig.
Add the chicken on top of the veggies. Any left over rosemary mixture can just be added to the vegetables.
Put it in the pre-heated oven at 160-180 degrees Celsius.
After the chicken is done (with a bird this big it took 2 hours) put it in the oven without a lid to let it brown.
When it is crispy take it out and serve.
It doesn't look like much but it is very yummy (especially with high quality chicken) and is very easy to make. Enjoy!
You can use all the leftovers (bones etc. ) to make a great chicken broth the next day. I use the same container, just add some water and fresh veggies (carrots, poree, celery root...).