Preheat your oven to 180°C (350°F) and generously grease a muffin tin or line it with paper liners.
In a large bowl, whisk together flour, sugar, brown sugar, baking powder, baking soda, and salt.
In another bowl, whisk eggs, milk, oil, and vanilla extract until smooth
Pour the wet ingredients into the dry ingredients and gently mix until just combined. Avoid overmixing to keep the muffins soft and fluffy.
Fold in the chocolate chips until evenly distributed.
Using a spoon or scoop, divide the batter evenly into the prepared muffin cups, filling each about three-quarters full for a big, rugged rise.
Bake in the preheated oven for 20-25 minutes, until the tops are golden brown and a toothpick inserted into the center comes out with moist crumbs.
Remove the muffins from the oven and let them cool in the tin for about 5 minutes, allowing their chaotic peaks to settle slightly.
Allow muffins to cool in the pan for 5 minutes, then transfer them to a cooling rack and let them cool completely.
Prepare the frosting by beating butter until creamy. Add powdered sugar gradually, then mix in vanilla and cream until smooth and fluffy
Divide frosting into separate bowls and tint with different Halloween colors using gel food coloring.
Spread or pipe colorful frosting over each cooled muffin.
Decorate with candy eyeballs, Halloween sprinkles, and chocolate chips to create different monster faces. Serve.