[notpushkin]

I think there was a way to preserve TLS handshake information in a way that something something you can verify you got the exact response from the particular server? I can’t look it up now though, but I think there was a Firefox add-on, even.

[account42]

I don't think how this can work. While the handshake uses asymmetric crypto, that step then gives you a symmetric key that will be used for the actual content. You need that key to decrypt the content but if you have it you can also use it to encrypt your own content and substitute it in the encrypted stream.