Preheat oven to hot, 200°C. Line an oven tray with baking paper.
Sift flour and mustard together into a large bowl. Rub in butter using fingertips until it resembles breadcrumbs (this can be done in a food processor if liked). Stir cheese and chives through. Season to taste.
Make a well in centre of the dry ingredients. Pour in combined milk and water, mixing quickly to a soft dough.
Turn onto a floured surface. Knead lightly and form into a 25cm round.
Transfer to tray. Bake for 35-40 minutes, until cooked when tested and base sounds hollow when tapped. Serve damper warm in wedges with butter.
For easy incorporation, you could try using Devondale Dairy Soft instead of butter.
Sprinkle the top of the damper with extra grated cheese before baking.
Replace chives with a combination of other herbs such as parsley and thyme.