Made my birthday cake and tried piping for the first time

I scanned my granny's recipes after she passed a couple years ago, and I decided to make one l've never tried before. I also made a couple alterations. Used King Arthur GF measure for measure since I can't eat gluten.
Used coffee in place of the water. Decided to try piping for the first time. That's why it looks so incredible. lol One day I'll get decorating down.

The last three pictures are the handwritten recipe. It doesn't have instructions. I also converted some of the measurements to grams.

360g flour

598g sugar

144g cocoa powder

340g buttermilk

340g warm water or coffee

100g oil

I mixed the dry ingredients in a large bowl.
Added eggs, buttermilk, oil, and vanilla.
Mixed for 2 minutes on medium speed. (I only have a hand mixer) Finally, added the coffee and mixed again. Batter will be thin. 2 greased 9 inch pans. 350° for 35 mins, but mine took about 40.

For the frosting, I made a much smaller batch. I'm not a big frosting fan, but I love cream cheese frosting. This turned out great without being too sweet.

1/2 c unsalted butter

8 oz cream cheese

1 tsp vanilla

1/4 tsp kosher salt

360g powdered sugar

48g cocoa powder