Rub potatoes with 1 teaspoon olive oil and bake for 50-60 minutes, until tender. Let the potato cool, then using your hands, rub off peel. Mash potatoes until smooth.
Meanwhile, in a saucepan, bring garlic, trout, and milk to a simmer over low heat. Remove from heat and let stand for 10 minutes. Transfer half of the trout to a plate and flake.
Transfer remaining trout, garlic, and milk to a food processor. Add lemon juice, paprika, and ½ cup olive oil and process until smooth.
In a large bowl, combine mashed potatoes, flaked trout, and contents of food processor. Mix together and add salt and pepper to taste.
Transfer mixture to a shallow 1 quart baking dish or four 6 ounce ramekins. Top with Parmesan. Bake until cheese melts and dip is heated through, about 20 minutes.
Serve with bread, crackers, cured meats, grapes, or other fruit.
Recipe by Things I Made Today at https://www.thingsimadetoday.com/2015/04/21/smoked-trout-dip/