Line a metal (or heatproof) 13x9-inch baking pan (or quarter sheet pan) with parchment paper with a few inches overhang on all sides. Alternatively, lightly grease the bottom of the pan and set aside.
Melt the butter in a heavy bottomed saucepan. Add the sugars, corn syrup, water and salt.
Once the mixture boils and begins to turn a light caramel color, turn the heat down in small increments to prevent it from scorching or turning dark too fast.
Cook on medium heat (turn down as the mixture starts to darken) stirring constantly until the mixture reaches 310 degrees (hard crack stage).
Remove the pan from the heat and carefully stir in the vanilla and almonds until well blended. Carefully pour the hot toffee into the prepared pan.
Once slightly set, gently dab the surface of the toffee with clean paper towels to remove any pools of butter that form on top. This will help the chocolate adhere to the candy. While the toffee is still very hot, sprinkle the chocolate chips over the toffee. When the chocolate chips are melted and soft, spread evenly on top of the candy using the back of a spoon.
Cool completely and break into bite size pieces. You can use a sharp metal spatula or knife to help break it apart.