In a medium pot, combine rinsed brown lentils with 3 cups of vegetable broth or water and 1/2 teaspoon of salt. Bring to a boil, then reduce heat, cover, and simmer for 20-25 minutes, or until lentils are tender but still hold their shape. Drain any excess liquid and set aside.

While lentils are cooking, heat olive oil in a large skillet or Dutch oven over medium-high heat. Add the sliced mushrooms and cook, stirring occasionally, for 8-10 minutes, until deeply browned and most of their liquid has evaporated. Do not overcrowd the pan; cook in batches if necessary.

Reduce heat to medium. Add the diced yellow onion to the skillet and cook for 5-7 minutes, until softened and translucent. Stir in the minced garlic, dried thyme, and black pepper, cooking for another minute until fragrant.

Sprinkle the flour over the mushroom and onion mixture. Cook, stirring constantly, for 1-2 minutes, allowing the flour to lightly toast and coat the vegetables.

Gradually whisk in 1.5 cups of vegetable broth, stirring constantly to prevent lumps, until the sauce thickens. Bring to a gentle simmer.

Stir in the unsweetened plain non-dairy milk (or dairy milk), vegan sour cream (or dairy sour cream), Dijon mustard, and tamari/soy sauce. Cook for 2-3 minutes, stirring, until the sauce is heated through and creamy. Do not bring to a rolling boil after adding sour cream to prevent curdling.

Gently fold in the cooked lentils and fresh lemon juice. Taste and adjust seasoning with additional salt and pepper if needed. Keep warm over low heat while preparing pasta.

Cook egg noodles or your preferred pasta according to package directions. Drain well.

Serve the lentil mushroom stroganoff hot over cooked egg noodles. Garnish with fresh chopped parsley.