Make the filling - to start, you'll beat the butter and peanut butter together until smooth. Next, add the powdered sugar, vanilla and salt. Mix until combined. You'll notice the mixture resembles cookie dough.
Freeze the filling - on a parchment lined baking sheet, roll out the peanut butter filling, about 1/2 inch thick. Freeze the filling for about 20 to 30 minutes. The colder the filling, the easier it will be to dip into chocolate
Melt the chocolate - in a microwave safe bowl or over a double boiler, melt the chocolate.
Cut out the hearts - once the filling is frozen, cut out the mini hearts.
Dip the filling - dip each heart into the chocolate and shake off the excess chocolate. If desired, sprinkle coarse salt on top.
Let cool - let the chocolates cool and set completely before serving.