Scrub potatoes under cold water and pat dry. Use a fork to prick the potato skins in several places.
Rub the potatoes with olive oil to coat then season with salt and black pepper.
Arrange the potatoes in a single layer in a slow cooker. Seal the lid and cook on Low setting for 2 1/2-3 hours. (To avoid burning, high heat is not recommended)
Use a fork to test for doneness. The fork should easily pierce the skin of the potatoes.
Lift the cooked potatoes out of the slow cooker and place onto a cutting board. With each potato, slice just across the top lengthwise then make a small cut across that line. Pinch and gently press the ends together to open up the potato. Add your favorite toppings and serve hot.
If not serving right away, switch the slow cooker to the Warm setting for up to 2-3 hours.