Gently heat olive oil in a large saucepan and add the chopped onion, carrots, celery, thyme and garlic. Saute until softened.
Add the vegan mince, stir into the vegetable mixture thoroughly, then add the stock, milk and ketchup/tomato puree.
Let gently simmer until thickened, another 5 minutes or so, and then add the drained lentils, soy sauce, and seasoning.
Taste for seasoning, you may want to add a little pinch of sugar, or a little more black pepper.
Finally, stir through the frozen peas, let cook for another couple of minutes then add to your baking dish.