Step 1

Preheat oven to 210c/410f.

Step 2

Bring a large pot of water to boil, then add bicarb soda - it will fizz a little.

Step 3

While the water is coming to the boil, peel your potatoes.

Step 4

Carefully add the potatoes, and boil for 20 mins or until very soft.

Step 5

When the potatoes have about 10 minutes to go, pour the oil into a metal roasting tin, and place in the oven to heat.

Step 6

When potatoes are soft, drain well then return to the pot. Give them a mix around in the pot to rough them up, if they break apart a bit that's fine too.

Step 7

Carefully add potatoes to now-heated oil, and turn well to coat them completely.

Step 8

Bake for 1 - 1 1/4 hours, tossing again about every 15 mins (add rosemary and garlic cloves with approx 15 - 30 minutes to go if using).

Step 9

Discard rosemary and garlic, add salt to taste and serve immediately.