In a food processor or a blender, process the granola until it resembles coarse crumbs. Transfer to a large bowl and add the peanut butter, protein powder, and sweetener. Use a silicone spatula to really work the ingredients in until the mixture clumps together. If it’s too dry, add a little water to help it bind together. Divide the mixture between 30 mini silicone muffin cups (or 16 large muffin cups), pressing down into the cups to even it out. Refrigerate 1 hour to firm up. In a medium microwave-safe bowl, combine the chocolate chips and butter. Heat on high in 30-second increments, stirring in between, until smooth. (Alternatively, you can heat them on low in a small saucepan). Drizzle over the top of the chilled cups and sprinkle with sea salt, if desired. Return to the fridge for 30 minutes until firm.