Preheat the oven to 400 degrees and line a baking tray with parchment paper. Cut the spaghetti squash in half lengthwise and scoop out any seeds.
Place the squash on the baking tray and coat the cut side (flesh) of the squash with olive oil (1-2 tablespoons) and sprinkle with salt and pepper. The turn the spaghetti squash over so skin is facing up. Cook for approximately 40 minutes. The squash is fully cooked when it's soft and stringy when pulled with a fork.
20 minutes before the squash is done, rinse and drain lentils with cold water and let sit out on the counter.
Heat a large pan on medium heat and add 1 tbsp of olive oil, onion, and garlic and sauté for about 5-8 minutes or until onion is soft and lightly browned.
Add in kale and carrots to the pan and sauté until veggies are soft, approximately 5-8 minutes. You can add a lid to cover your pan to help veggies cook faster and stir occasionally.
Add tomato sauce, lentils, Italian seasoning, and a sprinkle of salt and pepper to the pan and cook on medium to low heat until sauce starts to bubble. Keep sauce on low heat for 5-10 minutes.
Remove spaghetti squash from the oven and let cool for a few minutes. Using two forks, scoop out squash into a bowl. Top the squash with the lentil bolognese and ENJOY!