First order of business is to peel and slice the zucchini – I just used a knife and slice them around 1/8″ thick. You could do this a little thicker and/or use a mandolin (carefully!)
Cut the zucchini in half and then slice
Lay the slices out on large cookie sheets with paper towel under
Sprinkle with sea salt or Kosher salt
Leave at least 15 minutes to release water, then wipe water off and turn the pieces and salt again for another 15 minutes – then wipe again
While you are waiting for the zucchini, saute the onions and mushrooms, leaving the garlic until the last minutes just to heat until fragrant (one minute) and set aside
Preheat the oven to 350º F
Now brown the meat in the same fry pan you just used for the onions and mushrooms
Pour off the extra fat and set the beef aside
When the zucchini has finished “sweating” you want to bake it for 15 minutes in the oven to dry it out a bit
Remove the paper towels from the cookie sheets and place the slices one layer thick
Bake at 350º F for about 15 minutes – that should be enough to dry and soften the zucchini
Putting it Together
Spoon a layer of the thick sauce on the bottom of the baking pan
Add a layer of zucchini
Add a layer of the meat and sprinkle the mushroom and onions on top
Add another layer of sauce and then zucchini and again the meat and mushrooms
If you are using the white sweet potato, crumble it as the topmost layer
Cover and bake for 30 minutes or until a knife goes through easily
Uncover and cook for 10 minutes to get the top crispy before serving – or skip this step