►Heat oven to 350°F. Wash potatoes and prick all over with a fork. Microwave for 15 minutes, flipping every 5 minutes. If potatoes are still firm, microwave in 5-minute increments until they soften. Cool.
►Meanwhile, melt butter over medium heat in a large skillet. Add shallots and garlic
and cook 5 minutes, stirring occasionally. Add flour and cook 1 additional minute. Reduce heat to low and slowly whisk in milk. Add parmesan, nutmeg, pepper, and salt. Add crumbled goat cheese and stir until melted and smooth. Add spinach and stir. Cook 1 minute, or until heated through. Remove creamed spinach from heat.
►Halve potatoes and scoop out insides, leaving a ¼ inch of flesh inside each potato. Add potato insides to creamed spinach and stir until it becomes a cohesive mass. Thin with milk if mixture seems dry. Taste and season with salt and pepper as necessary.
►Place potato skins on a baking sheet. Fill potato halves with spinach-potato mixture. Bake 25 minutes. Serve warm.