Place peeled pears in large pot; add in orange peels and juice, spoon sweet, spices and 2 cups of sugar. Cover the pears with water. Bring to a boil over high heat, cover and continue to boil for 5 minutes. Turn off heat, continue to let poach for about an hour. Place overnight in the fridge.
Remove pears from liquid, pat dry with towel or kitchen paper. Reserve half the liquid.
Add chocolate and Mastiha powder to a double boiler, over hot (not boiling) water and melt chocolate. Remove from heat, stir in butter chips until melted. Placing the bowl on a tilt, dip the pears in chocolate (hold by the stem), rotating around until the entire bottom half is covered. Placing a spoon under the pears base (for support), place on non-stick parchment. Place in refrigerator until chocolate is hardened (about 30 minutes).
Add remaining cup of sugar to the poaching liquid and bring to a slow boil over medium-high heat. Continue to simmer until reduced to a syrup (this takes about 20-25 minutes). Serve pears on a small plate surrounded by the reduction and a dollop of whipped cream.