Lightly brown 2 tablespoons sesame seeds in a large stockpot over medium heat.
Melt in 1 stick butter,
add 14 ounces marshmallow cream
and 4 tablespoons chunky peanut butter. Stir constantly until smooth.
Remove from heat and mix in 9 cups rice crispy cereal
and 1/2 cup raw shelled sunflower seeds.
Transfer to a 9 by 13, lightly buttered cake pan. Pack lightly, smooth the top, and let sit for 45 minutes before cutting. Store covered at room temperature.
These are the best rice crispy bars ever.