Place the chocolate chips in a bowl and pop into the microwave for 30 seconds and repeat until most of the chips are melted. Stir well to ensure fully melted.
Spoon about 2 tablespoons of melted chocolate into one of the frog molds. Use a silicone pastry brush to coat the inside of the mold, bringing the chocolate all the way to the edges. Carefully lift up the mold and look underneath to make sure the frog is completely covered with chocolate, especially around the eyes. Repeat with the rest of the frogs, and put the mold in the fridge to set.
To Make the Peanut Butter Filling: Meanwhile, stir the peanut butter, icing sugar and salt together until they are well mixed. Using a small ice cream scoop, divide the peanut butter mixture into 1 tablespoon scoops. Place the scoops on a plate and place in the fridge to chill.
When the chocolate in the frog mold has set, lightly coat your hands with icing sugar to work with the peanut butter balls. Divide each ball in half, flatten and shape it to fit into the mold, leaving room for the top layer of chocolate.
Chill the mold in the fridge for a few minutes.
Fill in the rest of the frogs with the remaining melted chocolate by spooning it into each mold, making sure it fills in all the way to the edges to surround the peanut butter center with chocolate. Place the mold back in the fridge to set.
When the chocolate has fully set, slap the base of the mold on the kitchen counter and ease the frogs out one by one by getly pushing the bottom of the mold. Store your frogs in the fridge.