Preheat oven to 350°F. Line a 12-count muffin pan with cupcake liners.

In a stand mixer, cream the butter and sugar until fluffy and light in color, about 3-4 minutes.

Slowly add the eggs and vanilla, combining well after each addition. Scrape the bowl and add cocoa powder, mixing on low just until combined.

Sift the flour, baking powder, baking soda, and salt together. Add half of the dry ingredients to the bowl and mix on low speed.

Slowly stream in half the water, mixing just until combined, then scrape the bowl.

Add the remaining dry ingredients and remaining water, mixing on low just until combined. Scrape the bowl and fold the mixture a few times to ensure everything is incorporated.

Use a cookie scoop to divide the batter among the prepared muffin pan. Bake for 20-22 minutes until the cupcakes spring back to the touch or a toothpick comes out mostly clean. Allow to cool completely before decorating.

In a stand mixer, cream the butter for the frosting on medium speed until smooth and creamy, about 2 minutes. Scrape down the bowl.

Add powdered sugar, vanilla, salt, and heavy cream to the bowl. Start mixing on low speed until combined, then scrape the bowl.

Mix on medium-high speed for 2 minutes until the frosting is smooth and creamy.

Color about ½ cup of the buttercream green; divide the remaining buttercream in half, coloring one half light pink and the other half darker pink.

In a piping bag fitted with a number 80 piping tip, add a strip of the darker pink buttercream then fill the bag about ⅔ full with the lighter pink color.

In another bag fitted with a number 352 piping tip, fill it about ⅔ full with the green buttercream.

Hold the pink mum tip (tip 80) at a 45° angle and pipe a ring of petals around the outer edge of the cupcake. Continue piping more rings of petals towards the center.

Hold the leaf tip (tip 352) at a 45° angle and pipe leaves around the outer edge of the cupcake, under the outer mum petals.

Repeat the process for each cupcake.