In a large bowl, whisk together the flour, graham cracker crumbs, baking powder, baking soda, salt, sugar, and lime zest. In a small bowl or measuring cup, combine milk and key lime juice. Let sit for 2 minutes
Add eggs, vanilla, milk, and optional key lime extract to dry ingredients and whisk to combine. Let sit for 5 minutes.
Prepare griddle, preferably with shortening. Whisk batter before cooking. Using ladle or measure roughly 3-4 tablespoons batter, pour batter onto griddle and cook pancakes, turning once bubbles form on the top. Serve warm with sweetened condensed milk, maple syrup, whipped cream and graham cracker crumbs