Preheat oven to 350° F. Heat oil in a pan over a medium-high heat and sauté garlic and onion for 2 minutes or until translucent.
Then add mushrooms and lentils and sauté for another 2-3 minutes.
Transfer the mushroom mix into a food processor and add panko, Worcestershire sauce, parsley, and onion salt. Process until the mix is well combined but still a little chunky.
Take a cookie tray lined with parchment paper, and start rolling your meatballs into 2-inch-thick balls. Brush with olive oil then put them in the oven for 20-25 minutes.
Sauté your onions with olive oil in a pan for 2-3 minutes. Add in your mushrooms and continue sautéing for another 2-3 minutes. Set aside.
Add in all of your ingredients for the gravy into a sauce pan except for the cornstarch and your sautéed mushrooms and bring to a slow simmer. In a small bowl, make a slurry with your cornstarch and water and whisk until well combined.
Slowly incorporate the slurry into the gravy while whisking constantly. Add in your sautéed mushroom mix.
Serve over pasta or mashed potatoes and garnish with parsley.

For the vegan meatballs:
1 cup cooked lentils, from 1/2 cup dried
1 tablespoon olive oil, plus more for brushing
1 onion
4 garlic cloves
1 cup mushrooms, roughly chopped
3/4 cup gluten-free panko bread crumbs
3 tablespoon parsley
1 1/2 tablespoon vegan Worcestershire sauce
1/2 teaspoon onion salt
Salt and pepper, to taste

For the diane sauce:
1 tablespoon olive oil
1 cup mushrooms, sliced
1 medium onion, diced
1 cup vegetable broth
1 tablespoon vegan Worcestershire sauce
1 teaspoon Dijon mustard
1 teaspoon onion powder
1 tablespoon cornstarch plus 2 tablespoon water

For serving:
Mashed potatoes or pasta
Parsley, chopped