For the cupcakes: Preheat the oven to 350 degrees F. Line 2 muffin tins with cupcake liners.
Sift together the flour, cocoa powder, baking soda and salt in a medium bowl. In a large bowl with an electric mixer, beat together the granulated sugar, oil and eggs until completely combined and fluffy. Stir in the food coloring, vinegar and vanilla. Mix the dry ingredients into the wet, alternating in batches with the buttermilk, until completely combined.
Scoop the batter into the liners, filling them about two-thirds of the way full. Bake until a toothpick inserted in the center comes out clean, 20 to 25 minutes. Set on a wire baking rack to cool completely.
For the frosting: In the bowl of a stand mixer or in a large bowl with an electric mixer, beat the cream cheese and butter until fluffy and combined, about 2 minutes. Slowly add the confectioners' sugar and beat until combined. Remove 1/2 cup of frosting to a piping bag with a small round tip or a ziptop bag. Add the cocoa powder, melted chocolate, vanilla, food coloring and salt to the remaining frosting and beat until completely combined.
Using an offset spatula or butter knife, spread the chocolate frosting onto the cupcakes in an even layer, as flat as possible. Next, use the white frosting to pipe stitching onto each cupcake, one 2-inch line with 3 small cross-stitches. Serve on a green platter (for grass)!