Preheat the oven to 400℉.
In a large skillet, warm the oil over medium-high heat, then add the onion and sauté for 3-4 minutes, until translucent. Add the garlic and cook for one more minute.
To the skillet, add the lentils, rosemary, thyme, salt, pepper, Worcestershire sauce and tomato paste. Stir to combine and cook for 1 minute.
Now add the flour and stir well until incorporated and no clumps of flour or tomato paste remain.
Stir in the broth, peas and carrot mix and corn. Bring to a boil then reduce to a simmer and cook for 5 minutes, stirring occasionally.
Pour the lentil mixture into a 9x13 inch baking dish (or use your cast iron pan.) Spread it into an even layer, then spoon the mashed potatoes on top of the lentils. Spread them carefully and evenly.
Sprinkle the rest of the vegan cheddar on top, then bake for 25-30 minutes until hot. Serve immediately and enjoy!
Store leftovers covered in the refrigerator for up to 4 days. It can also be frozen once completely cooled.