Preheat your oven to 180°C (365°F).
In a large baking dish, place the chicken breasts and the block of feta. Drizzle the olive oil over them.
Sprinkle cajun seasoning generously over the chicken breasts and add a little to the feta as well. Then, add the cherry tomatoes to the dish.
Bake in the oven for 20 minutes.
After 20 minutes, take the dish out and add the spinach, ensuring it mixes well with the tomatoes and their juices.
Return the dish to the oven and bake for an additional 10 minutes.
While the traybake is finishing, bring a large pot of salted water to a boil and cook the orzo until it is al dente.
Once cooked, drain the orzo and rinse it under cold water until it is completely cooled.
Remove the traybake from the oven. Mash the baked feta and cherry tomatoes together, then shred the chicken breasts using two forks.
Add the cooked orzo and chopped fresh basil to the mixture, stirring until everything is well combined.
Season to taste before serving.
