Line a 9x13 inch pan with foil and spray with cooking spray.

Melt butter in a heavy saucepan over low heat. Stir in sugar, water, and corn syrup. Bring to a boil over medium-high heat, stirring until sugar dissolves.

Attach a candy thermometer and cook until the mixture reaches 290°F. Remove from heat, stir in vanilla and salt, then pour into the prepared pan.

Sprinkle chocolate chips over the hot toffee. Let sit for 2 minutes, then spread evenly with a spatula. Top with chopped almonds.

Allow the toffee to cool at room temperature for about 3 hours or until set. Break into pieces and store in an airtight container.