Set your silicon molds on the counter near your stove for later use.
Add 2 sticks of butter to a heavy sauce pan.
Melt over medium heat.
Next add the sugar, brown sugar, corn syrup, and water.
Stir for 2 minutes over medium heat with a heat proof or wooden spoon until well combined.
Clip a candy thermometer onto the side of the saucepan.
Turn up the heat to medium-high and bring to a boil, stirring constantly with a wooden spoon.
Continue to stir and cook until 240 degrees.
When it reaches 240 degrees, add the almonds and stir well.
Turn down the heat down to medium and continue to cook and stir slowly until 300 degrees (15-20 minutes).
Watch the color carefully. If it starts to darken beyond a light caramel color then turn the heat down as it may be beginning to burn.
Once it reaches 300 degrees, immediately remove from heat and stir in the vanilla and salt. CAREFUL as the toffee may bubble up as you add the vanilla.
CAREFULLY fill silicon molds 2/3 of the way full. This will be a messy job and don’t be concerned if you can’t fill them exactly 2/3 of the way or if you get it all over the top of the molds. It can easily be cleaned off later.
Let the toffee cool slightly for about 2 minutes and then sprinkle chocolate chips on top.
Let the chocolate sit on the warm toffee for about 3 minutes to melt and then spread the chocolate evenly over the toffee.
Sprinkle a little coarse sea salt (per preference) over the chocolate.
Let the toffee sit at room temperature until the chocolate is set (about 2 hours depending on your kitchen temperature). You can put them in the refrigerator to speed this process up.
Store at room temperature for up to 5 days.