Food processor

Tip the flour, garlic powder if using, salt and pepper into the food processor bowl. Briefly process until combined.

Dice the butter, add to the machine and process until the mixture looks like fine breadcrumbs.

Add both the grated cheeses and process again to combine.

With the motor running, add 2 tbsp of iced water and keep processing until a dough comes together. Add more water as necessary but drop by drop so you don't make the dough wet.

By hand

Sift the flour, garlic powder if using, salt and pepper in to a mixing bowl.

Grate in the cold butter, dipping it into the flour now and then if it sticks to the grater. Rub the butter into the flour using your fingertips.

Stir in the grated cheeses.

Add 2 tbsp of the iced water and stir in with a round bladed knife until the mixture starts coming together. Gradually add a little more water if necessary but don't make the dough wet.

Switch to your hands to bring together into a dough that leaves the bowl clean.

Transfer to a clean work surface, ideally covered with a silicone mat to reduce sticking, and briefly knead/fold into a smooth ball. Add a little extra flour if it seems sticky.

Cut in half, using scales for accuracy, then flatten into discs and wrap each half in cling film, foil or put in a reusable polythene bag. Chill in the fridge for 20 - 30 minutes.

Preheat your oven to 200° C /180° Fan /Gas 6 /400° F with a shelf in the middle position.

Cut two pieces of baking paper into rectangles 30 x 20 cm.

Have ready a shallow baking tray larger than the cut baking paper.

Lightly flour one of the pieces of baking paper (using too much flour can make the crackers hard).

Place one piece of dough on it (leave the other in the fridge), sprinkle with a little flour, and roll out very thinly until it covers the paper.

Prick all over with a fork, cocktail stick, blunt end of a bamboo skewer, or dough docker.

Neaten the edges of the dough with a knife or pizza wheel plus a ruler then cut into equal sized shapes: 5 columns by 4 rows will give you 20 rectangles (or choose your preferred size and shape).

Tip: can be chilled or frozen at this stage if liked.

Slide the paper and the cut crackers off the work surface and onto the baking tray.

Put in the preheated oven and cook until crisp and golden (approximately 9 - 12 min but watch carefully as ovens vary and the crackers can darken quickly).

Tip 1: If your oven cooks unevenly, turn the tray around after 6 minutes.

Tip 2: Crackers at the edges of the tray may cook more quickly than those at the centre, so move these to a cooling rack and return the rest to the oven.

Tip 3: If necessary, turn the crackers over for even cooking.

While the first tray is baking, roll and cut another batch with the remaining dough. When the first tray is done, bake the second.

Transfer all the cooked crackers to a cooling rack and leave until completely cold before storing in an airtight container and/or adding the cheese filling.

Put the soft butter into a bowl and start to break it down with a fork. Add both cheeses and work them into the butter with your fork: it may look like a lot of cheese and a small amount of butter but keep going until combined.

Add a pinch or two of your chosen seasonings then use a silicone spoon or similar to beat until thoroughly combined and smooth. Taste and work in more seasoning if needed.

Note. The crackers can become a little softer a few hours after filling. They still taste good, but if you want them at maximum crispness it's better to make up the sandwiches no more than an hour or two before eating.

Divide the cheese filling between half the crackers, spreading it evenly with a knife over their undersides.

Top each with another cracker, top side up, and press gently together.

Storing

If not eating straight away the sandwiched crackers can be kept in an airtight container at room temperature for 1 - 2 hours unless it's warm.

Otherwise, store in the fridge where they’ll keep at least three days. For the best flavour bring out 10 - 15 minutes before eating.