Spread all the nuts on ungreased baking sheet and bake until toasted, about
10 minutes, stirring once. Let nuts cool completely.
Line a shallow rimmed 15 x 10-inch baking sheet with parchment paper and
grease lightly with butter.
In a small bowl, place butter, vanilla extract and baking soda (no need
to blend); set aside.
In a heavy-bottom saucepan over high heat, bring sugar, corn syrup and 1/3
cup water to a boil, uncovered. While sugar cooks, brush down the sides of pan
with cool water. Boil sugar over high heat until it turns a light amber color,
about 12 minutes.
Remove from heat and quickly stir in butter, vanilla extract and baking
soda with a wooden spoon (the baking soda will make it foamy).
Stir in nuts until coated and spoon mixture onto prepared baking tray. Spread
brittle as thinly as possible.
Let brittle cool completely at room temperature.
Melt chocolate chips in microwave on medium, stirring every 10 seconds,
Crack brittle into desired serving pieces and dip halfway into melted chocolate
and place back onto greased parchment-lined baking tray to cool.
Sprinkle lightly with sea salt and allow chocolate to set.