In small saucepan over medium high heat, simmer lentils in 1 1/2 cups water until tender, about 20 minutes. Drain and set aside.
In large skillet over medium- high heat, cook bacon pieces until crisp. Lift bacon out and set aside. Add chopped onions and cook until just beginning to brown. Lift out and set aside with cooked bacon.
In large bowl, mix shredded potatoes, lentils, bacon/onion mixture, scallions and Panko. Beat egg and stir in. Portion about 1/2 cup mixture for each cake. Pat to form cakes.
In same skillet over medium- high heat, heat about 1/2 inch oil. Cook patties, a few at a time, until well browned, about 3 to 5 minutes. Turn and brown on other side.
Serve cakes topped with Mushroom Velouté Sauce.
1 tablespoon butter
4 ounces sliced mushrooms
1 tablespoon flour
1 cup chicken or vegetable stock
In large skillet over medium-high heat, melt butter. Add mushrooms and sauté until tender and beginning to brown, about 4 minutes. Stir in flour until blended. Stir in stock and cook and stir until mixture comes to a boil and is smooth and thickened. Keep warm.