Cook elbow pasta according to package directions, until al dente. Drain and set aside.
Cook red lentils according to package directions. Once lentils are cooked through, set aside.
In a separate large pot, heat butter or canola oil. Add in onion and cook until translucent.
Once onion is cooked through, add in remaining vegetables, garlic and spices. Saute for 10 - 15 minutes until vegetables are softened. I prefer to add my spinach last as it requires very little heat.
Sprinkle vegetables with flour, ensuring the mixture is well coated.
Add evaporated milk and ¾ cup of cheese, leaving some cheese for the last step.
Add in cooked pasta and lentils to the vegetable mixture and combine thoroughly.
Place mixture in a 9 x 13 dish, or two 8 x 8 dishes. Top with remaining cheese.
Bake for 20 - 25 minutes until cheese is bubbly.
Recipe by Carrots & Cake at http://www.carrotsandcake.ca/veggie-filled-mac-and-cheese/