Combine the broth and quinoa in a medium put on high heat and bring to a boil. Once boiling, reduce the heat to low, cover and simmer until all the water is absorbed, about 20 minutes. Add the cooked quinoa into a large bowl.
While the quinoa cooks, cook the turkey and garlic in a large skillet on medium-high heat until no longer pink inside, draining any excess fat and making sure to break up the meat. Add into the bowl with the quinoa. Additionally, heat your oven to 375 degrees.
Add the cucumber, onion, tomatoes, lemon juice, salt and a pinch of pepper into the bowl and stir until well mixed.
In a SMALL food processor (mine is 3 cups) combine all the tapenade ingredients, except the oregano and water. Blend until fairly smooth, stopping to scrape the sides down very often. Once mixed, add in the oregano and continue processing until broken down and you have a paste-like mixture.
With the food processor running, stream in the water until well mixed. Scrape the tapenade into the quinoa and stir until well mixed.
Stuff the peppers nice and full with the quinoa mixture, placing them into a large casserole dish, like a 9x13 pan.
Cover tightly with tinfoil and bake for 30 minutes. Then, remove the tinfoil, increase the oven temperature to 400 degrees and bake an additional 5-10 minutes, or until the peppers are as soft as you like them.
Sprinkle with feta cheese (if desired) and DEVOUR!