Mix flour, water, milk, sugar, yeast, and salt into a dough
Knead until smooth
Let the dough rest and rise until doubled
Chill the dough
Prepare a butter block
Roll the dough into a rectangle
Enclose the butter in the dough
Roll out the dough
Fold the dough into layers
Chill between folds
Repeat rolling and folding until layered
Roll the dough to final thickness
Cut into triangles
Shape into croissants
Place on a baking sheet
Let rise until puffy
Brush with egg wash
Bake at a hot oven temperature until golden brown
Cool slightly before serving