1. Melt 2 tbsp. of the butter in a medium-size heavy pot over medium heat. Add onions, pistachios, and almonds and saute for 3 minutes. Stir in rice and saute for 2 more minutes. Add stock, currants, pine nuts, cinnamon, and mastic. Season to taste with salt and pepper. Reduce heat to medium-low, cover, and cook until all liquid is absorbed, about 15 minutes. Add tomatoes and dill; adjust seasonings. Set pilaf aside; cover to keep warm.