Seasoning for roast potatoes. Seasoning for roast potatoes. Use 1.5 teaspoons of the Roast Potato Seasoning for 1 kg of potatoes. Mix the Roast Potato Seasoning with a little oil and add it to your roast potatoes towards the end. Hot tip: Don't add the spice mix to the pan at the beginning, as the spices burn quickly at high heat and lose their flavour. You can also use our Roast Potato Seasoning as a topping on chips. We promise, once you've tried our seasoning for potatoes, you'll never eat them without it again!