Drying boiled peanuts and making salted roasted peanuts in the shell by: Bret
It's not clear to me whether you want to make boiled then dried peanuts, or you are trying to make salted roasted peanuts in the shell. The two methods of preparation will taste different, and will have different textures.
Boiled peanuts can be placed in the oven and dried, but they don't taste like roasted peanuts.
Boiled and then dried peanuts have a unique taste and texture. The seasoning is concentrated, and the texture is somewhat chewy.
Boiled and dried peanuts are sold in Hawaii.
I made some boiled and dried peanuts, although I've never seen a recipe. I boiled the peanuts normally, then put a single layer of the boiled peanuts on a baking sheet. After preheating the oven to 320° F, I cooked the boiled peanuts in the oven for about 25 minutes, tasting samples until they were dried.
If you are trying to make salted roasted peanuts in the shell, then you do not need to boil and soften them for hours. To make salted roasted peanuts, you just need to saturate the peanuts' shells with brine before you roast them.
This can be done by soaking the peanuts in salt water, using about 1/2 cup of salt per gallon of water, which is 1 tablespoon of salt per pint of water. Soak them for 24 to 48 hours in brine, in the refrigerator in a ziplock bag, or in tupperware.
You could also simmer dried peanuts in salt water for 30 minutes, then let them soak in the brine as it cools. This will get the brine inside the shell and coat the peanut kernels with salt water.
After soaking the dried peanuts in salt water, you roast them in the oven at about 320° F for about 25 to 35 minutes. Place a single layer of the soaked peanuts on a baking pan. Sample the peanuts every few minutes, and remove them from the oven just before they taste fully roasted. The peanuts will continue to cook more as they cool, so be careful to not overcook them, as they will become bitter tasting.