Improved Dueling Riposte and Improved Twin Riposte allow you to Riposte with a two-handed weapon

Found a silly little RAW interaction.

Improved Dueling Riposte has the Dueling Riposte feat as a prerequisite, but allows you to use it even when not benefiting from Dueling Parry. Improved Twin Riposte does the exact same thing with Twin Riposte and Twin Parry.

Dueling Riposte has Dueling Parry as a prerequisite, and requires that you benefit from it, but this is what Improved Dueling Riposte allows you to ignore. Twin Riposte doesn't have Twin Parry as a prerequisite, so you can forgo it altogether.

You can take Dueling Parry at 2, Dueling Riposte at 8, and then wait until lv 12 to take Improved Dueling Riposte to use it with a Greatsword.

Or you can completely skip Twin Parry, take Twin Riposte at 10, and then wait until lv14 to take Improved Twin Riposte to use it with a Greatsword.