2: このケーキーをがべる (this is the "main sentence" in complex sentences)

Together, these two sentences become "master-slave complex sentences".

The clause subject "が" in the first sentence is "は" (otherwise "eating べる" is not satisfactory).

In the second sentence, the object "をは" is also used (otherwise "delicious しぃ" is not satisfactory)

In this way, both sides are satisfied. Moreover, "は" is a shot to the end and can be dominated at the end of the sentence. Grammar is correct. (But it seems better to use "たべる" in the end. In addition, it is more appropriate to change "ぉぃしくて" into "ぉぃからので", because "かかか "is more suitable for" か " )

There are many similar expressions, such as:

このりんごはぃからが (or "ははは" is ok) たくさ