Meanwhile, preheat the oven to 350F.
Prep the garlic, onion, carrots and mushrooms if not already done.
Add 2 tsp oil to a hot pan. I used a cast-iron skillet and cooked the whole dish in it. You could also use a regular pan and then add it to a baking dish to put into the oven.
On medium-low, cook onions for about 2 minutes or until they start to go translucent.
Add garlic and cook until fragrant, about 1-2 minutes.
Add carrots and cook for 3-4 minutes or until carrots begin to soften.
Add mushrooms and lentils. Cook for 1-2 minutes.
Add spices and tomato paste. Add salt and pepper to taste. Cook for 2-3 minutes.
Add vegetable stock and cornstarch and bring to a simmer for about 5 minutes.
Throw in frozen peas and corn and mix to incorporate.