Preheat oven to 350°F (175°C).

Line an 8-inch square baking pan with parchment paper; set aside.

Combine melted butter, oil and sugar together in a large mixing bowl. Whisk well for about a minute. Add the eggs, milk and vanilla; beat until lighter in color.

Sift in flour, cocoa powder, cinnamon, chocolate chips and salt. Gently fold the dry ingredients into the wet ingredients until just combined.

Pour the brownie batter into prepared pan, smoothing the top out evenly.

Bake for 45-50 minutes, or until the centre of the brownies in the pan no longer jiggles and is just set to the touch (the brownies will keep baking after they're removed from the oven).

Remove and allow to cool to room temperature.

Once the fudgy brownies have cooled, cut the brownies into 9 squares.

Place the frosting inside a piping bag. Cut the tip of the bag to make a small hole. Squeeze bag to pipe frosting over brownies in zigzag motion for mummy wrapping.

Place two eyes toward the top of each brownie.