Add the chocolate and coconut oil to a small bowl. Microwave in 20 second increments, stirring each time, until melted and smooth.
Pour the chocolate into the bottom of 6 large or 8-10 small Reese's-size molds. Tilt the mold to spread the melted chocolate over the bottom and sides of the molds. Transfer to the freezer and let set for 10-15 minutes or until firm.
Meanwhile, in a medium bowl, mix together the peanut butter, maple syrup, and protein powder until well combined.
Remove the molds from the freezer and spread a spoonful or two of the peanut butter mixture into the chocolate-coated molds, smoothing the top as best as possible. Reheat the chocolate until melted again, then spoon the remaining chocolate on top of the peanut butter and smooth flat.
Return the mold to the freezer and set until firm, about 5-10 more minutes. Remove and invert the Reese’s from the mold.