In large saucepan, heat coconut oil over medium heat. Add shallots, garlic, ginger, and chopped serrano pepper and cook, stirring often, until shallots are tender, about 3 minutes. Stir in curry paste and cook, stirring constantly, for a minute. Add coconut milk, turmeric, and soy sauce or aminos, stirring into curry mixture until well combined. Bring mixture to a simmer before stirring in cauliflower, squash, and tempeh. Reduce heat to medium-low, cover and let simmer, stirring occasionally, until cauliflower and squash are al dente, about 10 to 15 minutes. Remove lid from saucepan, stir in mango chunks, and let cook for another minute.