Preheat oven to 400 degrees F. Wash and prick the potatoes several times each with a fork and bake for 45 to 55 minutes, or until very tender and baked through. Remove from the oven and let sit for 10 minutes. (Increase oven temperature to 425 degrees F at this time). While the potatoes cook/sit, complete steps 2 and 3 below.
Heat the garlic-infused olive oil in a medium-sized sautee pan over medium-high heat. Once hot, reduce heat to medium, add the spinach and sautee until just wilted. Remove from heat.
Beat the milk with the goat cheese, yogurt, mozzarella cheese, salt, Italian seasoning and 3 Tbsp. of the parmesan cheese in a small mixing bowl and set aside.
After the potatoes have cooled, cut off the tops of each potato lengthwise and scoop out the pulp with a spoon, leaving ~1/4-1/2 inch thick potato shell. Scoop the pulp out from the potato tops as well and add to the other pulp, then discard the skin from the potato tops.
Add the potato to the bowl with the cheese mixture and mix until everything is evenly combined. If the mixture seems too dry/thick, you can add a little bit more yogurt and/or milk. Add only a little at a time, mixing after the addition, to avoid adding too much additional liquid. You don't want the mixture to be too dry but also don't want it to be runny.
Note: It's up to you how heartily you want to mix in the potato pulp. If you use an electric mixer, the end result will be a mashed potato-like consistency. If you mix by hand, you may still get some chunks of potato here and there.
Add the wilted spinach mixture and chopped artichoke hearts to the bowl and mix in gently by hand until everything is combined.
With the potato shells on the baking sheet, scoop the salmon mixture into the shells, dividing evenly and piling the mixture up above the tops of the shells. Sprinkle with the remaining 1/2 Tbsp. parmesan cheese, then bake in the preheated 425 degree F oven for ~20 minutes or until golden and heated through.
Serve the potatoes on their own as a main dish or as a side dish, whatever strikes your fancy!