In a medium bowl, combine the peanut butter powder, maple syrup, salt, and vanilla.
Add 2 tablespoons of Greek yogurt and stir until combined. The mixture may look dry at first—this is normal. Pinch a small amount between your fingers; if it holds together, it’s ready. If not, add 1 additional tablespoon of yogurt, stirring until the mixture is thick but moldable.
Line a baking sheet with parchment paper. Roll the peanut butter mixture into small balls and place them on the sheet. Freeze for at least 1 hour, or until firm.
In a microwave-safe bowl, combine the coconut oil and dark chocolate chips. Microwave for 40 seconds, then continue in 10-second intervals, stirring between each, until fully melted and smooth. Be careful not to scorch.
Remove the peanut butter balls from the freezer and dip each one into the melted chocolate, coating evenly. Return them to the parchment-lined baking sheet.
Place the baking sheet in the refrigerator for a few minutes, just until the chocolate has hardened. These taste best after resting overnight but can be enjoyed right away.
Store in an airtight container in the refrigerator for up to one week.