Preheat your oven to 350 degrees.
Chop the onion, garlic, red pepper, poblano pepper (be sure to get all the seeds out of this pepper, if there is any heat in this pepper, it lives there and in the white flesh when you cut it open), mushrooms and zucchini. You want them all finely chopped - try to chop them as evenly as possible.
In a large saucepan over medium heat, melt a tablespoon of butter, and a good dab of olive oil. Sautee the veggies, starting with the onion & garlic. Add in the red peppers, then the poblano, then the mushrooms, then the zucchini and finally the thawed out chopped spinach. In between all of the layers, sprinkle in the garlic powder, onion powder, and salt and pepper. Also, in between these layers add in a pat of butter so the veggies soak up the butter and get soft. This will take about 40 minutes to get the water out and get the veggies soft.
Once the veggies are cooked and on their way, get another large saucepan and on medium heat, put another pat of butter in and put 8 slices of the large poblano mushrooms in the pan. Flip a few times and once they look a little golden and saturated, transfer them to a plate.
To this pan, add another tablespoon of butter and the entire container of cream.
Make your cornstarch slurry - what is a cornstarch slurry you ask? Just put the cornstarch in a glass, add cold water and stir. It dissolves immediately and then add that to the medium heat cream and butter mixture, and stir with a whisk until it thickens. This can take a while, like 10 mins sometimes.
Chop your chives - and add them to the cream sauce. Add salt and pepper as you go here as well. You might need a few handfuls of salt (I use Maldon sea salt) to get the right taste. But do taste it before you use it!
Now, build your lasagna! Put a layer of pasta down, then top with the cream sauce, then with the veggies (I used a fork to spread it out evenly), then more cream sauce, then Italian cheese blend, then mozzarella, then do it all over again!
Once built, on the top, put large mushrooms and fresh sliced tomato. Sprinkle with salt and pepper. Cover with foil, being sure to not touch the cheese on top with the foil.
Cook for 40 mins with the foil on.
Cook another 20 - 30 mins without the foil until bubbly and a little browned.