Add water, yeast and sugar in bowl to combine. Stand for 5 min or until mixture becomes frothy/bubbly. (Thermomix: 2 min, 37C; sp 1)
Add flour, melted butter and salt then mix to combine (Thermomix: sp 5 20 sec).
Knead for 5-10 minutes (Thermomix: knead 4-6 min).
Place dough in oiled bowl, cover and leave in a warm place to rise until doubled in size (approx 45 min).
Preheat oven to 220C.
In a large saucepan, add bicarb to water and bring to a boil.
Turn dough out onto work surface and divide into 12 equal pieces. Roll dough into a long log and then form into pretzel shape and place onto a baking tray.
Place each pretzel into the boiling water for 30 sec then return to tray and brush with combined egg yolk and water
Bake for 10-15min until golden brown.
Cool on a wire rack and enjoy!