Heat a large skillet over medium-high heat and add 2 tablespoons of the olive oil. Put the turkey in the skillet and cook, separating the clumps of meat with a spoon or spatula, until crumbly and lightly browned, about 5 minutes. Transfer the turkey and any juices to a bowl. Reserve.
Add the remaining 2 tablespoons olive oil and the butter to a skillet and heat until hot. Add the garlic, onion and bell peppers, season with salt and pepper, and saute for 10 to 15 minutes, stirring occasionally.
Stir in the turkey, tomato, tomato paste, red wine, sherry, capers, raisins, olives, and scallions. Lower the heat to medium-low, season to taste, and cook for about 15 minutes until the flavors meld. Remove from the heat.
Combine the mashed potatoes and yuca in a large bowl. Lightly beat 2 of the eggs, and add to the potato mixture, along with the thyme, salt, black pepper, and cayenne. Cover and refrigerate for 30 minutes.
Form the potato mixture into balls about 1 1/2 inches in diameter. Using your thumb or forefinger, make a little well large enough to hold 1/2 tablespoon of filling in each ball. Add the filling and pinch the dough to seal. Pat the seam gently, then roll the ball to make it smooth and round.
Bring out 3 shallow bowls, Put the flour in 1 and season with salt and pepper. In another, beat the remaining 3 eggs with the water. Put the bread crumbs in the third bowl. Roll each ball in flour, then in the eggs, and then in the bread crumbs to coat.
In a deep fryer or deep pot, heat the oil to 375 degrees F. Drop the papas rellenas in the oil, in batches, and cook until golden brown, about 3 minutes. Remove and drain on paper towels. Serve.
Recipe courtesy of Norman Van Aken, New World Kitchen: Latin American and Caribbean Cuisine