Money Popeyes’ Cajun Flounder Sandwich debuts Thursday ahead of Lent and is like its Chicken Sandwich February 10, 2021 Kelly Tyko, USA TODAY Comments Off on Popeyes’ Cajun Flounder Sandwich debuts Thursday ahead of Lent and is like its Chicken Sandwich The new Cajun Flounder Sandwich debuts Thursday, Feb. 11 at Popeyes Lousiana Kitchen. It costs $4.49 and is similar to the chain's chicken sandwich.