Prepare the cake batter: Preheat your oven to 350°F (175°C) and grease a mini muffin tin (or line it with paper liners). In a medium bowl, whisk together the flour, sugar, baking soda, and salt. In a separate bowl, combine the melted butter, cocoa powder, buttermilk, egg, and vanilla extract. Stir the wet ingredients into the dry ingredients and mix until smooth.
- Bake the cake bites: Spoon the batter into the mini muffin tin, filling each cup about 2/3 of the way full. Bake for 8-10 minutes, or until a toothpick inserted into the center comes out clean. Allow the cake bites to cool completely in the pan.
- Make the frosting: While the cake bites are cooling, prepare the frosting. In a small saucepan, melt the butter over medium heat. Stir in the cocoa powder and milk, and bring the mixture to a simmer. Once it’s bubbling, remove from the heat and stir in the vanilla extract, powdered sugar, and a pinch of salt until the frosting is smooth and well combined.
- Frost the cake bites: Once the cake bites have cooled, dip the top of each one into the frosting or spoon the frosting over the top. Allow the frosting to set for a few minutes before serving.
- Serve: Once the frosting has firmed up slightly, your Texas Sheet Cake Bites are ready to enjoy!