Gather flour, sugar, salt, yeast, milk, water, butter, and egg wash
Mix flour, sugar, salt, yeast, milk, and water into a dough
Knead until smooth
Cover and let the dough rise until doubled
Chill the dough
Flatten the butter into a thin sheet
Roll the dough into a rectangle
Place the butter on the dough
Fold the dough over the butter
Roll out the dough
Fold the dough into thirds
Chill the dough
Repeat rolling and folding several times
Roll the dough into a large thin sheet
Cut the dough into triangles
Roll each triangle from the wide end to the tip
Shape into croissants
Place on a baking tray
Let rise until puffy
Brush with egg wash
Bake until golden brown
Cool before serving