Step 1

Wash strawberries and pat dry. Trim off any green or blemished areas.

Step 2

Mash strawberries roughly with a potato masher in a 6 litre heavy-based saucepan.

Step 3

Stir in sugar and allow to melt over a low heat. Do not boil.

Step 4

Add butter and increase heat until mixture is in a full rolling boil.

Step 5

Boil for 4 minutes only and remove pan from heat.

Step 6

Test to see if jam is set by putting half a teaspoon of jam onto a chilled plate, once cool push finger through and if jam wrinkles it is ready, if not return to boil and check at 2 minute intervals.

Step 7

Stir through black pepper and remove from heat. Skim off any foam.

Step 8

Immediately pour into sterilised warm jars and seal.