01 -
Preheat oven to 350°F. Line 8x8-inch baking dish with parchment paper or spray with nonstick cooking spray.
02 -
In a large bowl, whisk together flour, sugar, cocoa powder, salt, and baking soda until combined.
03 -
Add vanilla, vinegar, oil, and water to dry ingredients. Stir with spatula or whisk until fully combined.
04 -
Pour batter into prepared pan. Bake 30-35 minutes until toothpick comes out with a few crumbs. Let cool.
05 -
Using hand mixer, combine softened butter, cocoa, honey, vanilla, and confectioners sugar. Mix on low for 30 seconds.
06 -
Gradually add milk, one tablespoon at a time, until reaching desired consistency. Spread over cooled cake.