MIx cake batter, take egg, sugar, vanilla and mix well.
Add in melted butter and mix well.
Add in milk, add in all purpose flour, baking powder, salt. Fold gently.
Spoon this into the parchment paper lined baking pan. Bake till 30 to 35 mins.
Remove and cool completely.
Now mix all ingredients for frosting.
Once cake is cooled, spread frosting over it and serve.
Notes
1)You can make the frosting and the cinnamon butter spread in advance and store in fridge. Bring the cinnamon butterto room temparature before spreading. 2)Cinnamon Roll cake taste similar to cinnamon buns. 3)This goes well with coffee.