1. Toast almonds in a 350°F. oven for 8–10 minutes. Once cooled, chop nuts and set aside. 

2. Butter an 11x17-inch baking sheet and place on a heat-proof surface. 

3. Melt the butter in a heavy large saucepan over medium to medium-high heat (do not allow to brown). Stir in the sugar, water and corn syrup. Stir mixture until the sugar is completely dissolved. Once the mixture comes to a boil, Do Not Stir. Using a pastry brush dipped in water, wash down the sides of the pan to prevent any undissolved sugar crystals from coming into contact with the syrup. Attach a candy thermometer to the pan (do not allow tip of thermometer to touch the bottom of the pan). Without stirring, continue cooking to 300°F (hard crack stage). 

4. When syrup reaches the hard crack stage, immediately remove from heat and stir in vanilla extract and almond flavoring. Pour onto the prepared baking sheet. Evenly sprinkle the toffee with chocolate; as soon as the chocolate is melted, spread with a spatula to cover toffee completely. Sprinkle with the toasted nuts. 

4. Cool completely and cut into bite-size pieces. May be stored at room temperature for 7 days, or frozen for about a month. 

Makes about 2 pounds of toffee.