Ingredients:

Instructions:

  1. read Tom Clancy's The Sum of All Fears at about two-thirds of the way through the book. follow instructions therein.
  2. Choose target city to nuke.
  3. Hide bomb within city.
  4. Set explosive timer with generous countdown time
  5. Get the heck out of there

The hardest bit would be getting the fissionable material which is, to the detriment of potential nuclear terrorists worldwide, not readily available at your neighbourhood grocery store.