Combine flour, oil, water and salt. Stir to form a dough then kneed very well. Cover with oiled cling wrap then chill in the fridge for 1 hour.
Meanwhile, combine chicken, carrot, matzo, garlic and onion. Season with salt and pepper to taste.
Preheat oven to 180 degrees C. Remove dough from the fridge and kneed again. Roll out very flat, cut into 7cm circles then fill with a tablespoon of the chicken mixture. Fold up all sides to seal at the top of the knish.
Brush the tops with olive oil then bake in the preheated oven until cooked though and golden brown, about 45 minutes.