Peel the onions, cut them into small pieces and leave them in the clarified butter, add the grated carrots and let them stew a little. Season with salt and pepper.
Now add the tomatoes or tomato juice and let simmer.
Now layer a suitable casserole dish with the lasagne plates and the carrot-tomato sauce alternately. It may be that you have to break the records, but there are worse things, it's worth it.
Bake for about 45 minutes in the oven at 180 degrees, it depends on your oven, everyone heats and cooks differently.
About 15 - 20 minutes before the end, the cheese slices should be spread over them :) I like to eat something baked with cheese, that's why I have a lot on it, this amount decides for itself.
* Tip: since I juice a lot, I like to use the pomace for such recipes