Spread about 3/4 cup bolognese in bottom of dish. Top with lasagna sheets overlapping slightly. I used O'Sole Mio fresh lasagna sheets from my grocery's refrigerated section. The sheets are about 5x9 inches. For each layer of pasta I used three sheets. Two full sheets, and then I cut another sheet into two pieces to cover the additional space.
Sprinkle 1/4 cup of the parmesan and 3/4 cup of the shredded mozzarella. Top with about 2 cups of the bolognese, spreading with a rubber spatula, then 1 cup of the bechamel, also spreading with the rubber spatula to the edges.
Repeat pasta, parm, mozzarella, bolognese, bechamel two more times.
Finish with a layer of pasta, the remaining bechamel, and then the remaining bolognese. I like to place a few scoops of the bolognese randomly on top of the bechamel and then just slightly spread.
Then sprinkle remaining shredded mozzarella, also in random clumps here and there on top, then a sprinkle of the remaining parm. Dot the top of the lasagna with the small cubes of butter.
Cover with foil and place baking dish on a large baking sheet. Bake for 30 minutes covered, then remove the foil and continue to bake for 15 minutes uncovered until lightly browned and until the sauce is bubbly. Let stand for 10 minutes, then sprinkle with parsley, if desired.
Cut into squares and serve immediately.