The trick is to get everything cooked at the same time, so that the potatoes aren’t mush and your chicken raw. Finally ...

Add the rosemary and lemon zest and finely chop everything together. Put the chicken fillets into a large bowl along with a tablespoon of the olive oil and the garlic and rosemary paste.

Then add fresh minced garlic and next add your fresh chopped rosemary and slowly add in oil, whisk in oil until emulsified; ...