Preheat oven to 350°F (177°C, gas mark 4).

Add chopped bacon to a large skillet over medium heat. 

Cook bacon until partially crispy. Drain off 1/2 of the bacon grease (reserve for another recipe).

Increase the heat to medium high and add the mushrooms to the bacon and leftover bacon grease. 

Cook, stirring, until mushrooms release their liquid, the liquid evaporates, and the mushrooms begin to brown, about 10 minutes or so. 

Add the onions, garlic, thyme, a pinch of salt, and a few grinds of black pepper and cook for 3 more minutes. 

Add the vermouth or wine and cook until the wine mostly dissipates. 

Add the mushroom or chicken stock. Bring to a strong simmer and cook for about 10 minutes. 

Meanwhile, melt the butter in a separate medium pot over low heat. 

Once the butter has melted, add the flour and cook, stirring constantly, for 4 minutes. 

Heat the milk up to near boiling in another pot or in the microwave. 

Slowly whisk the milk into the butter/flour. I like to use a ladle to add 1 ladleful at a time. Whisk it in, then add another ladleful of milk. 

Keep slowly whisking until the sauce thickens. Season with a very small pinch of salt and some black pepper. 

Add 2/3 of the béchamel sauce to the mushroom mixture, and stir it in.

Reserve the other 1/3rd. 

Follow package directions for your lasagna noodles. Some can be added without cooking, others need to be blanched or partially cooked. 

In a casserole dish, lay down a thin layer of the mushroom mixture. 

Top with overlapping noodles, then another layer of mushroom mix. 

Sprinkle generously with Parmesan cheese. 

Keep layering like this until you’re out of sauce. Top with noodles, then pour over the reserved béchamel sauce, and a final big sprinkle of Parmesan. 

Put it into the oven and bake for 30 minutes. 

Let cook for 15 minutes or so, then cut into pieces with a sharp knife. 

Serve with a nice tart salad. Enjoy!