Mix together milk and vinegar and let sit while you chuck everything else into a bowl. Once curdled, mix in 'buttermilk' then knead until nicely combined (don't beat the life out of it though, you want it to be nice and rise-y so a good knead but don't over do it). Put roughly rolled, ping pong sized balls into a baking dish. Make sure they are all snuggled in fairly closely, you don't want them to spread at all, make it so their only way is up. Then bake at 160 deg cel until the centre rusks sound hollow when tapped. Break the rusks apart and pop back on oven trays and turn your oven down as low as it goes and let them dry overnight.