Using a food processor, pulse the mushrooms until they are finely chopped.
In a large pan sauté the mushrooms with a little drizzle of olive oil until they have sweated off most of their water, about 10 to 15 min. Set mushrooms aside.
For the filling
In the same large frying pan add a fresh drizzle of olive oil. Cook the onion until very soft and fragrant. Add the garlic and cook for a minute.
Add the pork mince and cook until golden brown around the edges. Add the carrots and cook until tender.
Add this cooked mushrooms and tomato purée. Bring to a simmer and cook for 20 min until the sauce has reduced and thickened.
Remove from the heat and set aside.
For the bechamel
In a large pan melt the butter. Once melted add the flour and whisk over medium heat until the mixture smells like biscuits.
Pour in the milk in a very slow stream whisking constantly. Whisk until all the milk has been fully incorporated.
Bring mixture to a simmer and cook until thick. Season well with salt. Remove béchamel from the heat and stir in the grated cheese.
For the lasagne
In a large pot of boiling salted water, boil the lasagne sheets according to package instructions. Once al dente, remove from water and lay the sheets out individually on a clean kitchen surface.
To construct the cups brush a muffin tin with a little olive oil. Place two cooked lasagne sheets across each other in each muffin cup. Trim off most of the excess while leaving some to get crispy in the oven.
Alternate layers of cheesy béchamel and mushroom mixture until the cups are full. Top with a little mozzarella.
Bake for 20-25 minutes until the lasagne cups are bubbling and golden brown.
Allow to cool slightly before removing from cups and eating right away or packing into lunchboxes.