Make the puree first. Bring a large pot of water to a boil. Then add the cauliflower, garlic and parsnips to the water. Boil for 10-12 minutes, or until the cauliflower and parsnips are very tender.
Drain the water and add the cauliflower, garlic and parsnips to a blender. Add the non-dairy milk, vegan butter and a few pinches of salt and pepper. Blend until nice and smooth. If you are having a hard time blending it, add a splash more non-dairy milk at a time until it blends. Taste and adjust seasoning. Set aside.
Now, make the filling. In a large pot, heat 1 tablespoon of olive oil on medium high. Add the onion.
Spread the onion out evenly in the pot. Just leave the onion alone for about 5 minutes to let them start to get brown. Then add the agave to the onions and toss to coat. Spread back out in the pan, and leave alone again. Reduce heat as needed. Toss and spread back out every 2-3 minutes until the onions are very brown and caramelized. About 15 minutes total.
Then add the garlic and carrots. Season with a pinch of salt and pepper. Saute for about 5 minutes to soften. Then add the mushrooms and drizzle the remaining 1 tablespoon of olive oil on top.
Toss the veggies together, then saute for another 10 minutes or until the mushrooms are brown and juicy. Season with another pinch of salt and pepper.
Now, add the tomato paste, and toss to coat the veggies with the tomato paste.
Next, add the flour to the veggies and toss to coat them.
Then add the vegetable broth, aminos or soy sauce, thyme, rosemary and a pinch of salt and pepper. Stir to combine and reduce heat to medium low. Simmer for a minute until it starts to get thick.
Add the corn and the peas, and continue to simmer for 2-3 minutes to begin cooking the corn and peas. Taste and adjust seasoning.
Preheat the oven to 400 degrees(F.)
Remove the sprigs of thyme and rosemary from the filling. Add the filling to an 8x8 inch baking dish. Smooth it out.
Then put the cauliflower puree on top. Smooth out then create texture with a fork so some of the tops brown nicely.
Bake for 15-20 minutes or until the top is nice and brown. Serve immediately.
Notes
*Make sure to chop the parsnips in small pieces so they are done at the same time as the cauliflower.