A simple combination to make this cheesy goodness.
This Potato Gratin recipe will be the talk of the table. Place the dried porcini in a measuring cup and pour on 1 1/2 cups boiling water, letting soak for thirty minutes. Line a strainer with a cheesecloth and place over a bowl. Drain mushrooms, collecting the broth in the bowl, then squeeze in cheesecloth to extract juices. Rinse several times and chop medium-fine. Measure out one cup of broth and set aside. Preheat oven to 375° F.
Rub inside of a 3 quart baking dish all over with the garlic clove half and lightly oil with olive oil.
Heat oil in a wide, heavy nonstick skillet over medium heat. Add onion and cook gently until just tender, roughly 3-5 minutes. Turn up heat to high and add cremini mushrooms. Cook, stirring, until they begin to sweat, 2-3 minutes. Then reduce heat to medium and add minced garlic, roasting mix, and porcini. Saute until fragrant, about 30 seconds, then season mushrooms with salt and pepper and cook for another 5 minutes. Add wine, continuing to stir until it is no longer visible in the pan. Taste and adjust seasoning.
Add potatoes and half the cheese to the pan and fold. Arrange this in an even layer in the baking dish.
Combine milk and mushroom broth, season with salt and pepper, and pour over potatoes. Press the veggies down into the milk and bake 1 hour, making sure to press the veggies down into the milk again halfway through. After 1 hour, remove and sprinkle remaining cheese on top and bake for another 30 minutes until top is golden and the sides are crusty. Let sit for 10 minutes before serving. Enjoy!