Soak peanuts in a large pot filled with water overnight. Drain the next morning. Since raw peanuts will float, you can use an appropriate-sized plate to weigh them down and keep them submerged.
Fill Masterbuilt fryer with water to the MAX line. Set heat to 375° F and bring to a boil. This will take approximately 20 to 25 minutes.
Add salt and seasoning to the boiling water. Place peanuts in the steamer basket and lower into water. Reduce heat to 250° F, and boil 4 to 6 hours, or until peanuts are cooked to desired tenderness. Note: Check water level if boiling for more than 60 minutes, and add more water as needed when evaporation occurs.