In a sauce pan combine squash and water and boil for 5 minutes or until semi soft. Let it cool for a while to room temperature.
Preheat oven at 350 degree Fahrenheit. Prepare a 9 inch square cake pan/baking dish with a liner or grease it.
Grind the pistachio roughly and keep it aside in a mixing bowl.
Grind the squash to a smooth puree along with the left over water to add to the nutrition.
In a bowl combine the beaten eggs, vanilla extract, and honey and mix well.
Add the squash puree to the egg mixture and mix well until well blended.
Pour the wet ingredients into the ground pistachio and mix well.
Make sure that the batter is well mixed but no need to overdo it. Just enough to mix the wet and dry ingredients.
Pour the batter into the cake pan and put the pan in the middle rack of the oven.
Bake for 30-35 minutes or until the knife comes out clean.
Take it out from the oven. Cut into square pieces.
Garnish with more ground pistachio or drizzle more honey/maple syrup.
Serve warm with your favorite beverage.