1Tbsp.black sesame seedI got mine at Williams-Sonoma
Place the dried chopped onion on a parchment lined baking sheet and toast in the oven for 3 minutes. Keep a close eye on the onion because it tends to burn rather quickly. You want it to be a nice golden brown. Cool, then place in a small bowl. Add next 4 topping ingredients and stir together. Set aside.
Preheat oven to 350 degrees. Line a large baking sheet with parchment paper. Set aside.
In a large bowl combine cheese, flour, butter and cayenne pepper. Using a pastry cutter mix together ingredients until they resemble coarse crumbs. Add the half and half and mix until dough forms a ball. Divide dough into 2 workable batches. Roll out to 1/4 inch thickness on a floured surface and cut. (I used a 1 1/2 inch fluted square cookie cutter) Place on prepared sheet about 1 inch apart.
Whisk together egg and water. Brush tops of crackers with egg mixture and sprinkle with everything topping mixture. Bake for 15-18 minutes or until golden brown. Repeat with remaining dough.