Prepare the lentil and tempeh bolognese (can be made a day in advance).
Prepare the tofu ricotta (can be made a day in advance).
Cook lasagna noodles according to package instructions. If using oven-ready noodles, there is no need to boil them.
Preheat oven to 400°F/200°C.
Spread a thin layer of bolognese on the bottom of a 9x13-inch**1 baking dish. Place 2-4 (depending on size of your baking dish) lasagna noodles on top (break if needed to fit the dish). Dollop some tofu ricotta on the noodles and spread to cover. Spoon more bolognese on top.
Repeat the layering process (noodles, ricotta, and bolognese) two more times so you end up with three layers of noodles. Sprinkle vegan mozzarella on top.
Cover the baking dish with foil and place into the oven for 30-40 minutes, until bubbling on the edges. Remove the foil and continue baking another 5-10 minutes to melt the cheese. If you want to slightly brown the cheese, you can broil for 1-2 minutes.
Remove from oven and let the lasagna rest for 10 minutes before cutting.
Notes
1) If you don't have a large casserole dish, you can use two smaller baking dishes such as two 8x8-inch pans or, what I did, a 7x11-inch pan (shown in photos) and an 8x8-inch pan. Prep and Cook Time include time required to make bolognese and ricotta. If you make these in advance, prep time will be 10 min and cook time 45 min.