1. Preheat the oven to 200°C. Line a shallow oven tray with baking paper.
   

2. Cut the potatoes in half lengthways, slice thickly lengthways then slice each piece into wide sticks.
   

3. Add a drizzle of olive oil to the tray then tip in the potato sticks and toss with your hands to coat them in oil. Dot potato sticks with the butter.
   

4. Place tray in centre of oven and bake for 5 minutes then remove and sprinkle with rosemary seasoning salt. Toss fries to coat in butter and seasoning.
   

5. Bake for 20 more minutes. Toss fries a final time and return to oven for a further 10-15 minutes or until lightly golden and crunchy at the tips.
   

Rosemary seasoning salt

1. Place the rosemary leaves and flowers and the rock salt in a high-speed blender. Blend until finely chopped.
   

2. Place the sea salt flakes in a large bowl and add the rosemary-and-salt blend. Stir until evenly mixed.
   

3. Transfer to a large airtight jar or several small airtight jars.
   

4. For easy access, put some of the seasoning salt in a small shaker jar and leave it beside the oven to use as an everyday seasoning for meat and potat