1. For the pesto, put basil, pine nuts, olive oil, lemon juice, 3 cloves of garlic and 1 tsp salt in a food processor and blend on high until desired paste consistency is reached.

2. For the casserole, pre-heat the oven to 350°F.

3. Put the sweet potatoes and remaining garlic in a large saucepan and add enough water to just cover.

4. Bring to a boil over high heat. Reduce heat to medium-low. Simmer, covered, for 20 to 25 minutes, until potatoes are tender.

5. Drain off the cooking water (storing it in a glass jar for sweet vegetable broth later).

6. Add 1/2 cup pesto, coconut milk and pecans and mash roughly in a food processor. Set the sweet potato mash aside.

7. In a pan, sautee onion in coconut oil until translucent.

8. Add lentils to the onion and cook for 5 minutes. Season with remaining salt to taste.

9. Place the lentil onion mixture in the bottom of a baking tray.

10. Top with pesto yam mash and bake oven for 20 mins at 350°F.

11. Store any leftover pesto in an airtight glass jar and refrigerate.