Preheat your oven to 350°F (177°C) and grab a 9" x 5" loaf pan. Lightly coat the pan with nonstick spray.

In a medium bowl, whisk together 2 cups of all-purpose flour, ½ cup of unsweetened cocoa powder, 1 teaspoon of baking soda, and ½ teaspoon of salt. Set aside.

In a large bowl, cream together ½ cup of unsalted butter and 1 cup of granulated sugar until light and fluffy—about 3-4 minutes.

Add 2 eggs to the butter-sugar mixture, one at a time, mixing well after each addition. Stir in 1 cup of milk and 1 teaspoon of vanilla extract.

Gradually add the dry flour mixture to the wet ingredients, gently mixing until just combined.

Gently fold in half of the crushed graham crackers and ¾ cup of mini marshmallows into the batter.

Pour half of the batter into the prepared loaf pan, spread evenly, sprinkle the remaining crushed graham crackers on top, then add the rest of the batter.

Top the batter with the remaining mini marshmallows.

Bake for 45-50 minutes, or until a toothpick inserted into the center comes out clean.

Let it cool in the pan for about 15 minutes before transferring to a wire rack to cool completely.