Add the butter and sugar and whiz until the mixture resembles breadcrumbs.
Add the milk a little at a time until the mixture starts to clump - you may not need all of the milk.
Bring the dough into a ball with your hands and shape into a cube.
Flour your worktop and roll the dough out to about 5mm in thickness. Trim the edges to make a square, then cut in half to form two rectangles.
Sprinkle most of the chocolate over one half (leave a little for the trimmings). Top with the other half and squish the edges together to seal.
Roll out to about 3mm in thickness, then cut into biscuit sized rectangles. Prick each one a few times with a fork and place on a lined baking tray.
Brush with egg white and place on lined baking trays. Bake for 15 minutes at 180℃ until golden. Leave to cool for a couple of minutes then place the biscuits on a rack to cool completely.
Notes
Will make between 20 to 30 biscuits, depending on size.Substitute currents for the chocolate to make a more traditional garibaldi biscuit.Maca powder would work instead of the mesquite, but neither are actually necessary.Please note: calories and other nutritional information are per serving. They're approximate and will depend on exact ingredients used.