01 - Set oven to 350°F. Line a 12-cup muffin tin with paper liners or lightly grease each cavity.
02 - Whisk together flour, graham cracker crumbs, both sugars, baking powder, baking soda, and salt in a large bowl until evenly distributed.
03 - In a separate bowl, whisk eggs, milk, Greek yogurt, melted butter, and vanilla extract until smooth and fully combined.
04 - Pour the wet mixture into the dry ingredients and gently stir just until incorporated; avoid overmixing to maintain tender texture.
05 - Fold chocolate chips and mini marshmallows into the batter with a spatula.
06 - Spoon batter evenly into prepared muffin cups, filling each about three-quarters full. Sprinkle additional mini marshmallows and crushed graham crackers on top.
07 - Transfer tin to oven and bake for 18–22 minutes, or until a toothpick inserted into the center of a muffin (avoiding marshmallow pockets) emerges clean.
08 - Allow muffins to cool in the tin for 5 minutes, then move to a wire rack for complete cooling.
09 - For a toasted effect, briefly broil muffins on high for 1–2 minutes after baking, watching closely to prevent burning.