1. Preheat your oven to 190C.
2. First, heat a generous knob of butter in a large frying pan. Add your sliced mushrooms, thyme and garlic and fry over a high-ish heat until they go black (not burnt) and all the liquid has come out of them. This can take a while, about 20-25 minutes. Set aside.
3. Cover your kale in cold water and bring to boil. Let it boil for 3 minutes. Drain and set aside.
4. To make your béchamel, simply place your butter, milk and flour in a large jug and microwave on high for 7-10 minutes, whisking every minute or so. It will suddenly thicken, when it does, turn your heat down to medium and cook for a further 6 minutes to cook out the flour. Once it's done, season, add mustard and set aside.
5. With all your components made, you are ready to assemble.
6. Ladle about a third of the béchamel into the drained kale and combine.
7. In a large baking / lasagne / pie dish, layer 3/4 sheets of lasagne, then add all your kale. Now sprinkle a third of your pine nuts over. Add 3/4 more sheets of pasta. Then your mushrooms. Ladle a second third of the béchamel over the mushrooms. A further third of nuts. Now 3/4 more lasagne sheets. Finally the last third of the sauce and the rest of the pine nuts. Crumble your stilton over fairly evenly. Bake for 25-30 minutes. Feed the most ardent meat eater and smile when they exclaim their appreciation!