Transfer the beef ragu from the slow cooker to a large pot or dutch oven on the stovetop over medium high heat.
Allow the ragu to simmer and reduce, stirring occasionally, for 15 minutes, or until almost all of the liquid has been cooked down and you’re left with a thick, beefy sauce.
While the ragu is reducing, cook the lasagna noodles according to the package directions.
In a small bowl, combine the ricotta cheese, sea salt, oregano, basil, parsley and ¼ cup mozzarella cheese.
Place 3 cooked lasagna noodles in the bottom of an 8 inch x 8 inch baking dish (trim the noodles to fit, if desired.)
Spread a layer of the ricotta cheese mixture on the noodles.
Place a layer of beef ragu on top of the cheese.
Place another layer of noodles on top of the ragu.
Top with the remaining ricotta and ragu.
Add the last 3 noodles on top of the ragu and finish it off with the remaining 2 cups of mozzarella cheese on top.