Preheat the oven to 180°C (350°F). Line a large baking sheet with parchment paper and set it aside.

In a microwave-safe bowl, combine the cream cheese, mozzarella cheese, and parmesan cheese. Microwave in 30-second intervals, stirring in between, until the cheese has mostly melted. Add the eggs and whisk together until a smooth batter forms.

Spread the batter evenly onto the lined baking sheet and bake for 15 minutes, or until the edges are firm. Remove from the oven and let cool.

Heat a non-stick pan over medium heat and add a drizzle of oil. Once hot, add the chopped onions and minced garlic, sautéing for 5 minutes until fragrant. Add the ground beef and cook for 3 minutes, stirring occasionally. Pour in the marinara sauce and continue cooking for another 5 minutes. Remove from heat.

Begin assembling the lasagna. Line an 8 x 8-inch pan with aluminum foil. Slice the keto lasagna sheet into six equal pieces. Place two pieces at the bottom of the pan, then layer with 1/2 cup of ricotta cheese, one-third of the meat sauce, and 1/2 cup of shredded mozzarella cheese. Repeat this process until all ingredients are used, ending with a layer of mozzarella on top.

Bake the assembled lasagna in the oven for 30-35 minutes, or until the top is golden brown and the sauce is bubbling. Remove from the oven and let it rest for 5 minutes before serving.