Heat oil over medium high heat in a heavy bottom skillet. Once hot, add garlic, shallot, lemongrass, and ginger until fragrant, about 2 minutes. Add in sweet potato, spinkle some salt over the potatoes. Then add in curry paste and cook, stiring often, about 2 minutes.
Add in coconut milk, water and turn down the heat to medium. Bring the mixture to simmer, and cook the sweet potatoes until soft, reducing the heat as necessarily to keep the mixture simmer. Cook for 15 minutes, until sweet potatoes are soften.
Add in bamboos shoots, red pepper, tofu and cook for another 3 minutes. Season with fish sauce, and sugar, according to taste. Remove lemongrass stalk and discard.
Add in Thai basil, remove from heat. Garnish with chopped peanuts. Serve over rice with a squeeze of lime wedges.
Start with 1 tablespoon green curry paste first and add more according to your preference.