Make the almond ricotta: drain soaked almonds and place 1/4 cup of the reserved soaking water into a blender or food processor with the almonds; pulse until a lumpy, ricotta-like texture forms, adding more soaking water a tablespoon at a time if needed.
Transfer the blended almonds to a clean container, stir in the probiotic powder until evenly distributed, cover with a clean towel secured with a rubber band, and place in a warm spot for at least 8 hours (10 hours is common) to ferment.
After fermenting, stir in 1 tablespoon olive oil, sea salt to taste, the grated garlic (if using), and a pinch of nutritional yeast (optional); seal and refrigerate until ready to use.
Make the spinach-walnut pesto: toast walnuts in a dry skillet over medium heat until fragrant and lightly browned, about 5 minutes, then transfer to a blender or processor with 2 cloves garlic, lemon zest, lemon juice, 2 cups packed spinach, 3 tablespoons olive oil, sea salt, and pepper; pulse to chop then blend to a chunky puree, scraping down the sides as needed.
Heat a 10–11-inch deep skillet over medium heat and add 1 tablespoon olive oil. Sauté the diced onion, carrot, and zucchini until the onion is translucent and the carrots soften, about 5 minutes.
Add 1/3 cup cooked French lentils, 2 minced garlic cloves, 1/2 teaspoon chili flakes, and salt and pepper; cook, stirring, until the garlic is fragrant, about 30 seconds.
Pour in the 3 cups (24 oz) tomato sauce, stir, and bring the mixture to a simmer.
Nestle the broken oven-ready lasagna noodle pieces into the simmering sauce, pushing them down to submerge as much as possible; cover and gently simmer until the noodles are just tender, about 15–17 minutes, adding 1/4 cup water and stirring if the mixture looks too dry.
Stir the noodles and vegetables to ensure all noodles are softened. Dollop the almond ricotta and spoonfuls of the spinach walnut pesto over the top, pushing them slightly into the noodles with the back of a spoon; scatter extra spinach if using.
Replace the lid and cook the assembled lasagna for another 10 minutes to heat through, then serve hot with an optional drizzle of olive oil.