To make the peanut sauce. Add all ingredients to a glass jar or blender and blend to combine, adding water as needed to thin the sauce. In a bowl, toss together the beef, a pinch of pepper, and the cornstarch (or arrowroot powder).Melt one tablespoon of butter in a large skillet over medium-high heat. Add the beef and curry paste. Cook until the beef becomes crispy, about 5 minutes. Add two tablespoons of butter, the garlic, lemongrass, and ginger. Cook until the garlic is lightly crisping, 1 minute. Reduce the heat to low. Add the tamari/soy sauce and Thai chili sauce. Cook for 2-3 minutes until the meat is caramelized. In a bowl, mix the mango, jalapeño, cilantro, green onion, sesame seeds, peanuts, and lime juice. Spoon the mango salsa over the bowls of rice. Add the beef, then pour the peanut sauce on top. Enjoy!