You will find Jamie's recipe here: https://www.jamieoliver.com/recipes/burger-recipes/bothams-burgers/

Adaptations:

Metallic taste: Swap red meat for white meat - chicken, turkey, pork.

Dry mouth & throat: Use chicken mince for moisture.

Constipation: Add fibre blend. Leave out the cheese.

Nausea: Add some ginger into the mixture.

Difficulty swallowing: Blend the add-in ingredients to a smooth paste.

Sore mouth: Blend ingredients to a paste. You can even blend the meat a little for a more consistent texture. Cover with foil in the oven to avoid crispness on the outside. Swap in soft leafy vegetables instead of the salsa.