2 Tbsp butter
1 Tbsp olive oil
1 onion, peeled, finely diced
¼ cup all-purpose flour
3 cup chicken or vegetable broth
1 cup 1% milk
½ tsp salt (or to taste)
¼ tsp nutmeg
¼ tsp paprika
large pinch black pepper
2 kg waxy potatoes (such as red-skinned)
2 Tbsp grated Parmesan cheese
1. In a large, heavy pot, melt butter into olive oil on medium heat. Stir in onion, cooking until translucent. Stir in flour. Gradually whisk in chicken broth and milk until blended. Add salt, nutmeg, paprika and black pepper. Remove from heat. Set aside to cool.
2. Peel and cut potatoes into halves (to allow fitting through food processor feeder tube). Slice paper thin using food processor slicer attachment (or hand-slice). Stir potato slices into cooled chicken broth sauce (Note: Texture of potatoes will be fluffier, less gummy, if chicken broth sauce is at room temperature rather than warm before simmering potatoes in it). Bring sauce and potatoes to simmer. Cover and cook, uncovering just to scrape bottom of pot a couple times. Stop simmering when potato slices begin to break up when stirred, about 8 minutes.
3. Spread mixture evenly in 2 1/2-quart glass or ceramic baking dish. Sprinkle with Parmesan cheese. (Tip: Can be assembled to this point to bake later). Bake 40 minutes on middle rack of oven, until potatoes are easily pierced with fork. Broil to brown. Let stand 10 minutes before serving.