Arrange almonds in a single layer on a foil-lined baking dish (11x7) or in a silicone brownie bite pan.
Combine butter, margarine, sugar, salt, and vanilla extract in a heavy pan. Cook over medium-high heat, stirring constantly until butter melts. Bring to a rolling boil.
Continue boiling and stirring for 5-7 minutes until the candy turns the color of almonds (about 300 degrees). Pour over almonds. If using a brownie bite pan, quickly distribute the toffee.
Cool completely. When cooled and set, spread chocolate over the toffee and sprinkle with ground walnuts.
Let the top set, then flip and repeat the chocolate and walnut process if desired. Store in airtight containers or cut into pieces.