Interesting question but CHALLENGE ACCEPTED
Since we know that with one flame the Twizzler will burn for 1 hour, with two Twizzler should burn for 30 minutes
So to start off, you light one Twizzler at both ends and the other twizzler only at one end simultaneously and
Once the Twizzler with both flames has burned out we know 30 minutes have elapsed and we only have 30 more minutes left on the other Twizzler
At this exact moment, we light the unlit end of the remaing Twizzler to half its remaing 30 minutes to exactly 15 minutes.
This means when this Twizzler burns out in exactly 45 minutes
*LAUGHS IN GENIUS*