lasagna is definitely "anything goes" You have your noodles, your sauce, ricotta (mix an egg and some thawed and drained frozen spinach into it ;-) and a layer in there of whatever veggies you like - mushrooms, peppers, onion, garlic, eggplant, broccoli... any combination is great when mixed with sauce and cheese!
To be honest I don't understand why anyone would add meat to an already rich and heavy dish like lasagna.
Have you had this before though? You mention it's "yummy". If you have had it and you know you like it - then you can always cut back the meat and "beef up" on the mushrooms. Also, ground turkey isn't nearly as heavy.
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