Spread oil on large rimmed baking sheet; set aside.
In large heavy saucepan, bring granulated sugar, butter, water and light corn syrup to boil over medium-high heat, stirring occasionally, until candy thermometer registers 300°F (150°C) or hard-crack stage when spoonful dropped into cold water separates into hard brittle threads, about 8 minutes.
Remove from heat.
Whisk in cocoa; stir in almonds.
Quickly spread as thinly as possible on prepared pan.
Let cool completely.
Break into pieces.
Make-ahead: Store layered between waxed paper in airtight container at room temperature for up to 1 month).