Cook the couscous according to the instructions on the package. Drain well and season with salt and pepper to taste. Set aside.
In a bowl mix together the beef, bread, milk, Worcestershire sauce, salt, and pepper until fully combined. Then form into even sized balls.
Preheat a saute pan on medium heat. Once hot, add the oil. Brown the meatballs well on all sides. Move the meatballs to one side of the pan and add in the mushrooms. Saute the mushrooms until they start to soften.
Add in the broth, cream, sage, and butter. Mix everything together and bring to a simmer. Cook, turning the meatballs occasionally, until the sauce reduces and thickens to a creamy consistency. If needed: add the cornstarch mixture a little at a time if needed to thicken the sauce to a creamy conssitency.
In a nonstick pan on medium heat warm the pita on both sides. Then cut into wedges.
Serve the meatballs with pita and couscous. Garnish with parsley.