Preheat and Prepare
Preheat the oven to 350°F (175°C). Grease a mini muffin tin or line it with mini cupcake liners.

Make the Chocolate Mixture
In a saucepan, melt the butter with water and cocoa powder over medium heat until smooth. Let it cool slightly.

Mix Dry Ingredients
In a large bowl, whisk together flour, sugar, salt, baking soda, and cinnamon.

Combine Wet and Dry
Pour the cocoa mixture into the dry ingredients and stir until partially combined.

Add Eggs and Sour Cream
Add eggs, sour cream, and vanilla extract. Mix until the batter is smooth and shiny.

Fill and Bake
Spoon the batter into the mini muffin cups, filling each about 3/4 full. Bake for 10–12 minutes, or until a toothpick comes out clean.

Cool Slightly
Let the bites cool in the tin for 5 minutes before transferring to a wire rack.

Make the Glaze
In a saucepan, melt butter with milk and cocoa powder. Bring to a light boil, then remove from heat. Stir in powdered sugar and vanilla until smooth.

Dip and Garnish
Dip each cake bite into the glaze or spoon it over the top. Sprinkle with nuts if using. Let the glaze set before serving.