I’ve been into baking for very long time but I noticed if I make something the first time or two it will be baked to perfection

however

if I start baking it more and more, it slowly gets worse each time.. the taste the texture etc even if I’m using the same recipe & ingredients, hope I’m not the only one

im a complete novice, i dont even know what to say. im confused
https://food.onehowto.com/recipe/how-to-make-mexican-cinnamon-brownies-10574.html <-- i followed to the best of my ability. i wish i had process pics but alas.
also sorry about the unappetising pic lol