Line your baking sheet with either a silicone mat or parchment paper. Set the sheet aside for now.
Use a stand or handheld mixer with the paddle/whisk attachment and blend in the butter on medium-high (2 to 3 minutes) until creamy. Add the peanut butter and keep it mixing (1 to 2 minutes) until combined.
Lower the speed and toss in the powdered sugar, salt, and vanilla. Blend this mix on low (2 to 3 minutes) until slightly crumbly.
Scoop out about a tablespoon of the peanut butter mixture and roll it between your palms into a 1-inch ball (about 32 to 35 balls in total). Set each ball on your prepared baking sheet.
Refrigerate the balls (1+ hour to 24 hours, your choice).
Put the chocolate and oil into a microwave-safe bowl, then microwave in 20-second bursts, stirring each time until glossy. Let the chocolate sit for a few minutes after melting.
Pull your peanut butter balls from the fridge, then drop each one into the chocolate and give it a good roll for full coverage. Lift the ball out (wait a few sec for all the excess chocolate to drip off) and slide it onto your baking sheet. Optional: drizzle leftover chocolate or throw in some sprinkles.
Pop the balls back in the fridge for about 30 to 35 minutes before serving. Enjoy!