Prepare all ingredients as directed above.
Steam sweet potato for 10-15 minutes until tender, then drain and blend in a high speed blender with coconut milk until completely smooth. Set aside.
Add ½ tbsp olive oil to a large skillet and sauté garlic and marjoram for 1 minute until fragrant.
Add sweet potato and coconut milk, white wine, nutritional yeast, liquid smoke and salt & pepper to taste. Simmer mixture for 15-20 minutes until fragrant and thick. (If sauce is ready before next steps are complete, turn down to low and keep stirring occasionally to avoid burning. If mixture becomes too thick add a little water.)
While sauce is cooking, bring a large pan of water to a boil and add pasta. Cook uncovered as per package instructions, then rinse and drain. Set aside.
Heat remaining 1 tablespoon oil in a small skillet and add mushrooms and tempeh. Sauté for 10 minutes - stirring frequently – until tempeh is golden. Season to taste with salt and pepper.
Add mushrooms/tempeh to sweet potato sauce. Add pasta and gently stir to combine.
Serve in large bowls decorated with marjoram leaves, chili flakes and extra pepper. Enjoy!