01 - Preheat oven to 350°F. Grease and line an 8-inch square baking pan with parchment paper.
02 - In a large bowl, whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt until well combined.
03 - Add buttermilk, vegetable oil, egg, and vanilla extract to the dry mixture. Beat until smooth, then gradually pour in hot water while mixing.
04 - Pour batter into prepared pan. Bake for 25 to 30 minutes or until a toothpick inserted in center comes out clean. Cool completely in pan.
05 - While cake cools, whip heavy cream with powdered sugar, vanilla, and softened cream cheese until medium-stiff peaks form. Refrigerate until ready to use.
06 - Break the cooled cake into small pieces and crumble into coarse bits using hands or a fork.
07 - Fill clean flower pots or dessert cups with alternating layers: crumbled cake, creamy filling, more cake crumbs, then a generous topping of chocolate cookie crumbs to resemble soil.
08 - Arrange edible flowers, mint leaves, and fresh herb sprigs on top to create a whimsical garden appearance.
09 - Refrigerate assembled desserts for at least 30 minutes to allow flavors to meld and texture to set.