Line 2 12-cup cupcake pans with liners.
In a small bowl mix together the graham cracker crumbs with the sugar, then add the melted butter and stir until combined.
Scoop a packed teaspoon of the graham cracker mixture into each cupcake liner. Pack down the graham cracker crumbs using a tamper or the back of a spoon.
Set the pan aside until the batter is ready. If you have any extra graham cracker mixture you can sprinkle it on top of each cupcake before (or even after) baking.
Preheat the oven to 350°F. Place the unbroken eggs in a bowl of warm water to bring them to room temperature, set aside
Sift the flour, cocoa, and baking soda into a mixing bowl. Add the salt and whisk well to combine, set aside.
In the bowl of a stand mixer, fitted with the flat beater, beat the softened butter on medium speed for 1-2 minutes. Scrape down the sides of the bowl.
Add the sugar and vanilla to the butter and mix on low until incorporated, then beat on medium speed for 2-3 minutes until the butter is light a fluffy. Scrape down the sides of the bowl.
Add the eggs one at a time, mixing on low speed after each addition until well incorporated. Be sure to scrape the bowl in between additions.
Add the flour mixture to your mixing bowl in 3-4 batches alternating with the milk. Scrape down the sides of the bowl and mix well (about 30-40 seconds) after each addition.
Fill each cupcake liner with about 1/4 cup of batter. I like to use a #16 disher/scoop to portion out my cupcake batter. You can find them in restaurant stores or online.
Bake @ 350°F for 20-22 minutes or until a wooden toothpick comes out clean. Let the cupcakes cool in the pan for 10 minutes, then remove onto a cooling rack. Once cool frost with Fluff Frosting
In the bowl of a stand mixer, fitted with the flat beater, beat the softened butter, fluff, and vanilla extract together on medium speed for 1-2 minutes. Scrape down the sides of the bowl.
Sift in half the powdered sugar. Mix on low speed until incorporated, then mix on medium speed for 2 minutes.
Scrape down the sides of the bowl again, then sift in the remaining powdered sugar. Mix on low speed until the powdered sugar is incorporated, then mix on medium speed for another 2 minutes.
Top each cupcake with fluff frosting. A pastry bag fitted with a #1M tip is great for this!
I always use a stand mixer to make my batter and frosting, but you can use a hand mixer as well.