Heat oven to 450°. Pierce potatoes all over and place in microwave on paper towels. Microwave 9 to 10 minutes or until soft when pressed. Let cool slightly.Advertisement
Meanwhile, melt 1 tbsp of the butter in a large cast-iron skillet over medium-high heat. Crumble in turkey and cook, breaking apart with a spoon, 3 minutes. Stir in carrots, shallots and garlic; season with 1/2 tsp of the salt. Cook 5 minutes. Stir in spinach and peas and cook 2 minutes.
Whisk broth, water, flour and 3 tbsp of the dill. Add to skillet and stir to completely coat mixture. Remove from heat.
Cut up potatoes and mash with milk, remaining 2 tbsp butter, remaining 1/4 plus 1/8 tsp salt, 3 tbsp dill and crumbled feta. Spoon onto turkey mixture and spread to pan edges. Bake at 450° for 15 minutes, until bubbly and lightly browned.