Step 1: Prepare a large baking sheet by lining it with parchment paper or a silicone baking mat. This is a crucial first step for the best homemade toffee recipe.
Step 2: In a heavy-bottomed medium saucepan, combine the salted butter, granulated sugar, and salt over medium heat.
Step 3: Stir the mixture constantly with a wooden spoon or heat-resistant spatula as the butter melts and the sugar dissolves.
Step 4: Continue cooking and stirring until the mixture reaches a boil. Attach a candy thermometer to the side of the pan, ensuring the bulb is submerged but not touching the bottom.
Step 5: Cook the mixture, stirring frequently to prevent separation, until the thermometer reaches 300°F (149°C), which is the hard-crack stage for the best homemade toffee recipe.
Step 6: Immediately remove the pan from the heat and quickly stir in the vanilla extract and half of the chopped almonds.
Step 7: Carefully pour the hot toffee onto the prepared baking sheet and spread it into an even layer (about 1/4 inch thick).
Step 8: Let the toffee sit for 1-2 minutes, then sprinkle the chocolate chips evenly over the top. Let them sit for another minute until softened.
Step 9: Use an offset spatula to spread the melted chocolate into a smooth, thin layer across the top of the toffee.
Step 10: Sprinkle the remaining chopped almonds over the wet chocolate. Let the toffee cool completely at room temperature for several hours until set.
Step 11: Once fully hardened, break the toffee into pieces by hand or with a knife. Store in an airtight container.