Step 1

Put a cast iron fry pan or heavy non-stick pan over a high heat and allow it to get hot.

Step 2

Cut the lemon into quarters and place them cut side down in the hot pan. Once the lemon is charred turn to char the other cut edge.

Step 3

Remove from the pan and set aside to cool.

Step 4

put the rosemary, coriander seeds and gin into a cocktail shaker or measuring jug.

Step 5

Use a wooden spoon to lightly bash the aromatics.

Step 6

Divide the ice between two large round bottomed glasses.

Step 7

Strain the gin into your glasses.

Step 8

Top up with tonic water, stir briefly and add in your charred lemon quarters.

Step 9

Serve  immediately with a small pinch of whole peppercorns.