Preheat oven to 350 degrees F.
Lightly oil a 12-muffin or cupcake pan. Heat oil over medium-high heat in a large skillet and cook onion, carrots and celery until soft, about 10 minutes.
Sprinkle a dash of salt while cooking.
Stir in garlic, mushrooms, thyme, and sage. Let cook another 5-8 minutes and remove from heat.
To the bowl of a food processor, add lentils, brown rice, tamari, and broth. Pulse to combine, then transfer the cooked vegetables and the breadcrumbs to the processor, along with the lentil mixture, and pulse again till combined. The mixture should still have visible bits and pieces and not be mush.
Taste and season with salt and pepper.
Using a large spoon or an ice cream scoop, place equal amounts of mixture into prepared muffin cavities. Pack down using the back of the spoon.
Bake for 15-20 minutes depending on size of muffin pan. They are done when browned on top and slightly firm to the touch.
Remove from oven and let rest for 5 minutes.
Slide a knife along the edges then place a baking tray on top and flip upside down.
Serve over mashed potatoes and top with gravy.

2 tablespoon olive oil
1 large onion, diced
2 large carrots, diced
4 stalks celery, diced small
4 cloves garlic, minced
4 fresh sage leaves, minced (or 1 teaspoon dried sage)
2 teaspoon dried thyme
2 cup cooked French lentils
1 (8-oz) package mushroom, finely chopped
1/4 cup tamari or soy sauce
2/3 cup vegetable broth
1 cup cooked brown rice
1/2 cup bread crumbs
Sea salt and freshly ground black pepper to taste