Place the flour in a large bowl, add the yeast and salt, then stir in the oil and enough of the measurement water to form a firm, sticky dough. Knead the dough for about 5–10 minutes using a dough hook in an electric mixer or on a well-floured surface by hand until smooth and elastic. Put the dough in a lightly oiled bowl, cover with a tea towel and leave to rise in a warm, draught-free place for 1 hour until doubled in size.
Knock back the dough, then divide into 2 pieces and roll out each piece into a long, thick rope. Cut each rope into 16 pieces and then roll into balls. Cover loosely with a lightly oiled piece of clingfilm and leave to rest for 5 minutes.
Roll each ball into a short log and taper the ends, then place on 2 lightly greased large baking sheets, leaving a little space between them. Beat together the egg yolk and 1 tablespoon water, then brush a little over the breadsticks and sprinkle over the sesame seeds. Bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 10–15 minutes until golden. Transfer to a wire rack and leave to cool.