Use butter or margarine to butter the inside of your slow cooker.
Cut out a piece of parchment paper large enough to line the bottom while extending up the sides of the slow cooker.
Place the chocolate and butter in a microwave safe bowl.
Next, melt the butter and chocolate together on high while stirring at 30 second intervals.
Once melted allow the chocolate and butter mixture to cool.
When cooled whisk in the sugar.
Next, whisk in the eggs, vanilla and the salt.
Add the flour to the mixture and stir well for about 2 minutes.
Stir in the chopped walnuts and pour the mixture into the prepared slow cooker.
Cover the slow cooker with the lid and cook on low heat for about 2 hours and 15 minutes.
Not all slow cookers are made equally and the cooking times can vary. I added 10 extra minutes to the cooking time.
You will want to look for edges that are thoroughly cooked while the center is somewhat softer.
When the brownies are ready, remove the inside container from the slow cooker and allow to cool for about 1 hour with the lid on.
Once cooled run a rubber spatula around the brownies.
For easy removal, hold on to the excess parchment paper and pull up then out onto a cutting board. (This is easier if brownies are completely cooled)
Slice the brownies into squares or use a 2 or 3 inch heart shaped cookie cutter to form the hearts. (you can also do a combo of small and bigger hearts)
Drizzle the brownie pieces with melted chocolate and top with sprinkled pecans.