Melt butter in saucepan over medium high heat

Whisk in flour until smooth

Slowly add in milk while continuing to whisk over medium high heat until fully incorporated

Turn heat up slightly and continue to whisk as you bring liquid to a slight simmer

Continue until sauce is thickened enough to coat/stick to a spoon (about 3-5 minutes)

Add a pinch of salt to taste and set aside

Spread olive oil on bottom of pan (and you can add a couple of spoonfuls of sauce too, if desired)

Now it's time to create your first layer: 5 noodles, 1 1/2 - 2 cups bolognese, 1 cup béchamel and 1 - 1 1/2 cups shredded mozzarella plus 1/2 cup grated parmesan

Repeat for second layer

For final layer: skip the béchamel sauce

Cover with foil

Bake at 375 for 30 minutes

Remove foil and continue to bake until browned and bubbly, about 10-15 more minutes

Remove from oven and let stand for at least 15-20 minutes before slicing