Line a 11x7 inch baking dish with foil or prepare a silicone brownie bite pan with 24 sections. Arrange almonds in a single layer in the prepared pan. Set aside.

In a heavy saucepan, combine butter, margarine, sugar, salt, and vanilla extract. Cook over medium-high heat, stirring constantly, until butter melts and mixture comes to a rolling boil.

Continue boiling and stirring for 5-7 minutes until the candy turns a golden caramel color (~300°F). Quickly pour or scoop the toffee over the almonds in the prepared pan.

Allow the toffee to cool completely, about 2 hours.

Once cooled and set, spread melted chocolate over the top. Sprinkle generously with ground walnuts. If making both sides, do this process twice. Let the chocolate set before breaking into pieces.