Line a 13 by 9 glass baking dish with parchment paper.

Place a layer of graham crackers on the bottom of the dish, reserving enough for the top.

Grind the remaining graham crackers into 1 and ½ cups of graham cracker crumbs.

Melt 1 and ½ sticks (¾ cup) of unsalted butter.

Add ¾ cup of granulated sugar, ¼ cup of packed light brown sugar, and ¼ teaspoon of salt to the melted butter. Stir together.

Whip together one large egg into ½ cup of milk.

Slowly pour the milk and egg mixture into the sugar and butter mixture, stirring constantly to prevent curdling.

Bring the mixture to a rolling boil over medium-low heat, stirring constantly.

Once the boil is stable, remove from heat.

Add 2 tsp of vanilla extract, 1 and ½ cups of sweetened shredded coconut, and 1 and ½ cups of graham cracker crumbs.

If using pecans, reserve about a half a cup of the coconut and replace it with a half a cup of chopped pecans.

Stir until the mixture starts to thicken and pull away from the bottom of the pan.

Pour the mixture into the prepared baking dish over the graham crackers.

Spread gently.

Top with the reserved graham crackers, filling any gaps with broken graham crackers if desired.

For the icing, combine 2 cups powdered sugar, ¼ cup softened unsalted butter, 2 tsp vanilla extract, and 3 tbsp milk.

Whip the icing ingredients until smooth and creamy.

Spread the icing over the top of the cookie bars.

Chill in the refrigerator for at least 2 hours.

Store in an airtight container in the refrigerator.