Slice the mushrooms and shiitake into thick pieces. Tear the shimeji into bite-sized pieces by hand. Cut the bacon into pieces around 1cm thick.
Boil plenty of water in a large pot, add salt and then the pasta.
Combine the egg yolk, mustard, and heavy cream from the "A" ingredients in a bowl and mix. Add a pinch of salt and pepper and set aside.
Add olive oil to a heated pan and then brown the bacon. Then add the mushrooms all at once. Season lightly with salt and pepper.
Once the mushrooms become tender, turn off the heat and let it sit for a moment.
Boil the pasta according to the directions on the package. Drain, then add it to the "A" mixture and quickly toss. Then, add to the pan and mix with the residual heat. Season with salt.
Add a bit of lemon juice, transfer to plates and top with parsley to complete.
Story Behind this Recipe
Something I thought of after receiving some Maille mustard for taste testing.
Be sure to render the bacon. Once you've added the pasta to the bowl, toss quickly! You don't need the lemon juice, but it gives a fresh aftertaste. I didn't use Parmesan cheese (powered cheese) since it would detract from the fragrance of the mustard and mushrooms, but you can add it if desired.