How long do you cook an 8.5 kg turkey?

It's impossible to give you an exact cooking time without knowing the oven temperature you'll be using.

Here's a general guide, assuming an unstuffed turkey and standard oven temperatures:

* 325°F (160°C): 4-5 hours

* 350°F (175°C): 3.5-4 hours

Important considerations:

* Stuffing: If you're stuffing the turkey, it will take longer to cook. Check the stuffing's internal temperature to ensure it reaches 165°F (74°C).

* Size: An 8.5 kg turkey is large, so make sure it's fully cooked.

* Oven type: Different ovens can vary in temperature, so you may need to adjust cooking time.

* Thigh temperature: The most accurate way to determine if your turkey is done is to check the internal temperature in the thickest part of the thigh. It should reach 165°F (74°C).

Always use a meat thermometer to ensure your turkey is cooked to a safe temperature.

Here are some additional tips:

* Rest the turkey: After cooking, let the turkey rest for 15-20 minutes before carving. This will allow the juices to redistribute.

* Basting: You can baste the turkey with pan drippings or butter during cooking, but it's not necessary.

For more detailed information and specific cooking time recommendations, I suggest checking out a reliable recipe website or cookbook.