The packaging has been designed to be "clean and simple" and focuses on creating natural cues, conveyed through the use of illustration in the window of the packaging. Pearlfisher said it was aiming to communicate strength, honesty and integrity through the design.
Square Pie was launched in 2001 as an "honest British food brand" in a simple brown-board box. Pearlfisher's brief was to help translate the success the brand had into the supermarket experience.
The new format is being launched as a phased roll out and will be stocked in Sainsbury's.
Natalie Chung, designer at Pearlfisher, said: "The packaging is like the product, straightforward and simple -- it is what it is.
"It's a superb product and we wanted the design to emphasise this and not create any distraction. It's simply there to enhance."