You're talking stuff but Sanae's just not listening.

Ditzy Sanae reminds me of Hirasawa Yui.

It is an older sister. I must eat it.

I suppose she could be thinking in terms of "an older sister gives me CANDY AND CAKE" instead of trying to think of someone specific.

...Yukari and Mima as role models?

Sanae seems to be the sane one here.

It's confusion on Sanae's part. She's trying to think of Kanako, but she thought about how sweet Kanako is and that resulted in thinking of cake and candy.

Fact is, she's trying to form a thought and that's what's important.

FRUITS (lol)

A rather nice example here.