Have ready an 8-inch square metal pan. For thinner treats a 9-inch square pan will work. For a half batch, use a 9x5 or wider loaf pan. Line with parchment.
Have all your ingredients lined up and ready because this recipe moves fast. Have half the halvah crumbled for the mixture and half crumbled to go on top.
Melt and brown the butter in a large nonstick pot. As soon as it starts to turn brown, add the marshmallows. Keep the heat low so as not to burn the butter.
Stir marshmallows over low heat until melted, then add the tahini, pistachio butter, vanilla and salt. Remove from heat and stir in the cereal, half of the halvah. and half of the pistachio nuts.
Transfer mixture to pan and press down with a second sheet of parchment. Sprinkle remaining crumbled halvah and chopped pistachios over the top. If you happen to have some toasted sesame seeds, sprinkle some on.
Let cool completely, then lift from pan and cut into large squares.