Get shan nihari masala, it makes yummy nihari... so perfect everytime. Be careful with the semolina/flour though... you really would have to add it slowly and gradually and just the right amount otherwise you will end up with huge lumps of flour in your nihari. (it's not that difficult though)
However, if you would like to make it from the scratch try
www.khanapakana.com
www.desicookbook.com
www.cookingwithbj.com
or Fauzia pakistani recipe site
for lassi:
Blend together 2-3 (depending on how rich you want you lassi to be) cup of yogurt (desi style one) with a cup of milk... while blending add in sugar according to you taste and a couple of ice cubes. You can also add a pinch of salt and/or mango slices if your hubby prefers salty and/or mango taste.
PS: for nihari ask the butcher for the nihari or Bong meat with nalli(marrow bones) as nihari made with this meat is quite tastier than the nihari made with the regular other beef parts.