1. Bring a large pot of salted water to a boil and cook the egg noodles according to package directions until just tender. Drain, toss with a small drizzle of olive oil to prevent sticking, and set aside.

2. While the water heats, warm the olive oil and butter in a large deep skillet over medium heat. Add the chopped onion and cook for 4 to 5 minutes, stirring often, until softened and translucent.

3. Stir in the sliced mushrooms and a pinch of salt. Cook for 7 to 8 minutes, stirring occasionally, until the mushrooms have released their liquid and turned deep golden around the edges.

4. Add the minced garlic, soy sauce, Worcestershire sauce, Dijon mustard, tomato paste, smoked paprika, dried thyme, black pepper, and remaining salt. Cook for 1 to 2 minutes, stirring, to coat the vegetables and bloom the flavors.

5. Pour in the vegetable broth and stir in the rinsed lentils. Bring the mixture to a gentle boil, then reduce the heat to low, cover, and simmer for 20 to 25 minutes, stirring once or twice, until the lentils are tender but still hold their shape.

6. If the pan ever looks too dry before the lentils are cooked through, stir in an extra splash of broth or water. If there is too much liquid when the lentils are ready, let the mixture simmer uncovered for a few minutes to reduce slightly.

7. In a small bowl, whisk together the cornstarch and cold water to make a slurry. Stir the slurry into the skillet and cook for 1 to 2 minutes, until the sauce thickens and turns glossy.

8. Reduce the heat to low and stir in the sour cream or Greek yogurt until the sauce is smooth and creamy. Do not let it boil once the dairy is added, or it may curdle.

9. Taste the stroganoff and adjust the seasoning with more salt, pepper, or a splash of lemon juice if you like a little brightness.

10. To serve, spoon the warm egg noodles into bowls and top generously with the lentil mushroom stroganoff. Garnish with chopped fresh parsley and enjoy right away.