Place the sourdough starter, warm water, strong white bread flour, granulated sugar and sea salt into a bowl and mix until a dough forms.

Transfer to a work surface and knead for 8–10 minutes until smooth. The dough will feel firm rather than soft and elastic.

Return the dough to the bowl, cover and leave to prove until doubled in size.

Divide the dough into 12 equal pieces, around 80 g each. Roll each piece into a ball, then shape into long ropes. Twist into pretzel shapes, or leave as bread sticks.

Divide the dough into 6 equal pieces. Roll into balls, then shape into long ropes and twist into pretzel shapes.

Place onto lined trays, cover and leave to prove while preparing the water bath.

Heat the oven to 200°C.

Bring the water to the boil in a pan and carefully whisk in the bicarbonate of soda.

Lower the pretzels into the water, 2–3 at a time, and poach for 30 seconds. Remove with a slotted spoon and return to the trays.

Beat the egg with the water to make an egg wash, then brush over the pretzels. Sprinkle with sea salt or your chosen seeds.

Bake for 20–25 minutes until deep golden brown.

Transfer to a wire rack and allow to cool slightly before serving.