Dual Group One winner Egg Tart has returned to her best form to win the Group Two PJ O'Shea Stakes at Caloundra and head towards a Caulfield Cup mission.

Ridden perfectly by Leith Innes on Saturday, Egg Tart ($2.30) came from near the tail of the field but had the field covered at the 250m.

She came away to win by 2-1/2 lengths to Tradesman ($6.50), with a half-head to Megablast ($5.50) in the 2200m race.

Egg Tart had not won since taking the Group One Schweppes Oaks in Adelaide and Group One Queensland Oaks last winter.

But she showed she was back on track with a second to stablemate Comin' Through in the Group One Doomben Cup two weeks ago.

Trainer Chris Waller had been toying with spelling Egg Tart after the Doomben Cup but decided to extent her Queensland stay by one run.

Waller's Queensland manager, Paul Shailer, said it was hard to believe Egg Tart had not won another race for a year after her impressive Oaks form last year.

"But she is coming back to her best after a couple of interrupted preparations. Chris was keen to test her at the 2200m again and that is why she is here today," Shailer said.

"She will it has spell here in the sunshine and then Chris is keen to see how she measures up to a race like the (Group One) Caulfield Cup in the spring."

Innes was also very impressed with the way Egg Tart has returned to form since she got back out to a middle distance.

"I wish they were all as easy as that," Innes said.