I should say thanks?

[flytothesky]

Hello~
Could you help me what will be the most natural way to say in this conversations?

A: It's my fist trial pan-cake, would you like to eat some?

After eating...

B: Oh, it's yummy for the first tiral. Thanks for the nice food!

A: No,, I should say thnaks you! (or I should thanks you!)
Thanks for willing to be my guinea pig.

B: No, worry, Whenever you cook new food you can just test on me~

[Anglika]

Hello~
Could you help me what will be the most natural way to say in this conversations?

A: It's my fist trial pan-cake, would you like to eat some?

After eating...

B: Oh, it's yummy for the first tiral. Thanks for the nice food!

A: No,, I should say thnaks you! (or I should thanks you!)
Thanks for willing to be my guinea pig.

B: No, worry, Whenever you cook new food you can just test on me~

A : Here's my first attempt at a pancake. Would you like to try it?

B: Oh, it's yummy. Well done.

A: Thanks for being my guinea pig. I'll make some more now.

B: Well, you can use me as a guinea pig at any time if that's a trial run.

[flytothesky]

Many thanks for your help Anglika

Sorry but would you tell me how to say this please?

I should say thnaks you!
or I should thanks you!
or I'm the one who should say thanks)

I'm wondering how native english speakers express this.. Thanks a lot~

[Anglika]

I'm the one who should say thank you/thanks