Preheat the oven to 375°F.
In a large stockpot, heat half the olive oil over medium-high heat. Add both the turkey sausages together and cook, stirring frequently, and breaking up the meat so that it’s very crumbly and browned throughout, about 4 to 5 minutes. Turn it into a strainer and let it the fat drain off.
Add the remaining oil to the same pot, without cleaning it, over medium heat. Add the onion and shallots, and cook, stirring frequently, until softened, about 5 minutes. Add the garlic, oregano and basil and cook, stirring, until you can smell the garlic and herbs, about 2 minutes.
Add the canned tomatoes and red pepper flakes if using, and stir to combine everything. Bring to a simmer over medium high heat, stirring occasionally. Add the cooked sausage, lower the heat to medium low and simmer, stirring occasionally, for 20 minutes. Taste, and season with the salt and pepper.
Meanwhile, in a medium bowl, beat the eggs lightly. Add the ricotta, basil, oregano, and salt and pepper, and stir to blend. Stir together the gouda and havarti in a bowl.
Ladle a little of the sauce onto the bottom of a 13x9-inch baking pan. Spread all 12 of the lasagna noodles with even amount of the ricotta mixture, laying them out on a counter. Place 4 ricotta-covered noodles into the pan, covering the bottom. Spoon over about 1 1/2 cups of the sauce, covering the ricotta mixture entirely. Evenly sprinkle over 1/3 of the shredded cheese mixture. Repeat until you have three layers.
Cover the lasagna with tin foil (hint: spray one side with nonstick cooking spray and place that side down on top of the lasagna – when you remove it, the cheese won’t stick to the foil). Bake for 1 hour, removing the foil halfway through the cooking time so that the top gets bubbly and browned. You may wish to put a baking sheet (with sides) on the rack below the lasagna pan, to catch drips.
Let the lasagna sit for at least 10-15 minutes before cutting it, so that the pieces hold together better.