• Preheat the oven to 350°F
• Spread the almonds onto a baking sheet in an even layer and roast them for 8-10 minutes, stirring them half way through the cooking time.  As soon as you begin to smell a nutty aroma, remove them from the oven and allow them to cool.  
• Place the cooled almonds into a food processor and pulse them until they are finely chopped.  A sharp knife can also be used.  
• Chop the chocolate either by hand or in the food processor and set it aside.  
• Coat a 12x16x1-inch baking sheet with non-stick oil spray and line it with parchment paper or foil. Leave enough overhanging to use as a handle to lift the finished toffee.  Coat parchment/foil with non-stick oil spray.  

Cook the Toffee:

• In a large, heavy-bottomed saucepan set over medium heat, add the butter, sugar, water, corn syrup and salt.  Stir constantly as the butter melts and the sugar dissolves.  Clip a candy thermometer to the pan and bring the mixture to a boil.
• Cook the mixture, stirring frequently, until the temperature reaches 300°F to 310°F (hard crack stage).  Be patient and do not wander off from the stove.  As the temperature climbs past 280°F keep a close eye on it as the temperature will increase quickly.
• Once the toffee has reached 300°F, remove the pan from the heat and let sit for 30 seconds to settle the bubbling then stir in the vanilla.  
• Pour the toffee into the prepared baking sheet and spread to an even thickness with an off-set spatula.  

Add the Chocolate and Nut Layers:

• Sprinkle the chocolate evenly over the hot toffee and let it melt about 3 to 5 minutes.
• Once the chocolate has melted, spread it evenly over the top of the toffee using the off-set spatula .
• While the chocolate is still warm and soft, sprinkle the surface with the chopped almonds and gently press them into the chocolate.   Allow the toffee to cool completely 6-8 hours, preferably overnight, then break the toffee into pieces by using the tip of a sharp knife. 
• Store in an airtight container in the refrigerator for up to 1 week.