Line a baking dish (11x7 inches) with foil, or prepare a silicone brownie bite pan (with 24 bites). Arrange almonds in a single layer on the prepared surface. Set aside.

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

Continue boiling and stirring for an additional 5-7 minutes, or until the candy reaches the color of almonds (approximately 300 degrees Fahrenheit). Pour the hot toffee mixture over the prepared almonds. If using the brownie bite pan, use a small metal scoop to carefully fill each bite with toffee, working quickly.

Allow the toffee to cool completely.

Once the toffee is completely cooled and set (this usually takes about 2 hours), spread the melted milk chocolate evenly over the top of the toffee. Sprinkle generously with the ground walnuts. If you plan to coat both sides, use only half of the chocolate and walnuts on the first side, allowing it to set before flipping and coating the other side. Once fully set, carefully pop the toffee bites out of the silicone pan or cut the toffee into pieces. Enjoy!