bake a cake ("Baking a cake" sounds a little more natural.)

My baby wanted to eat a cake tonight, I had to cook bake (In English, we tend to use "to bake" for sweet things in the oven, like cakes or cookies.) a cake for her even though I was so lazy for baking felt too lazy to bake.

(This part sounds like it came from the recipe with a few changes. However, the sentences are missing grammatical subjects, like "I separated/whisked..." Make sure to be consistent with all the verbs.)
First, I separated the egg white from the yolk.
Second, I whisked the egg white, adding in caster sugar gradually, continue whisk until stiff peaks formed. At the same time, if you up-end the bowl, egg white would be still in the bowl. (This second sentence sounds like it came straight from the recipe. Notice that the grammatical subject is "you," but you're writing about yourself making the cake, I think.)
Third, I whisked the yolk, added in caster sugar, flour and milk, mixed them and then set them aside.
Fourth, I mixed the egg white and yolk mixture, whisked them up and down, avoiding on going in the same direction.
At last, after Pre-heating the oven, I began to bake baking the cake about 10 minutes. (You can bake a cake for ten minutes, but you can't really "begin" baking a cake since it's a very one-time action.)

(I would add an adverb here, like "Finally" or "At last" or "After baking" to complete the story.) The cake without any additive(s) was done ! Delicious and safe! ("Safe" here sounds a little extreme here. I might say "healthy" instead.)

严格地说，这篇文章不完全是我写的，借助了字典，好多单词不能确定用哪个，请赐教，谢谢!