In a medium saucepan over medium heat, melt butter. Whisk in sugar and agave and bring mixture to a simmer, stirring occasionally until caramel is golden brown and slightly thickened. Remove from heat and stir in baking soda, vanilla, and almonds.
Working quickly, use a cookie scoop to scoop almond/caramel mixture into 1-in clusters onto a parchment paper-lined baking sheet. Drizzle clusters with melted dark chocolate and chill 30-60 minutes until clusters are firm. Enjoy!