To cook the Rice: Melt the butter over medium heat in a large pot. Add the turmeric and cumin and cook 1 minute. Add the rice and stir to coat. Cook, stirring freqently, until the rice is lightly toasted, about 4 minutes. Add the chicken broth, season to taste with salt and pepper. Raise the heat to high and bring to boil. Cover, reduce to simmer and cook for 15 minutes without disturbing. Remove from heat, keeping the cover on, and let rest for 5 minutes.
For the White Sauce: Combine all the ingredients together.
For the Turkey: Heat a large saute pan or frying pan over medium-high heat with the butter. When bubbling, add in the onion and cook for 5 minutes. Pour in the turkey drippings (or chicken broth) and bring to simmer. Add in the leftover turkey and cook for 1 minute just to warm through. Remove from heat, stir in 1/2 of the White Sauce.
Wrap the stack of pita bread or flatbread in damp towel. Microwave on medium for 60 seconds to soften and heat through
To serve, divide the lettice, tomato and red onion amongst each plate. Spoon rice onto each plate and top with the turkey. Add a spoonful of the remaining White Sauce onto each plate (you can use this as salad dressing for the salad or just spoon on top of the turkey). Serve with Harissa-style hot sauce.