Preheat the oven to 350 degrees and line a mini muffin pan with paper liners.
Melt the butter in a mixing bowl, then stir in the sugar until combined.
Add the egg and mix until smooth.
Stir in the flour, cocoa powder, and salt until no dry streaks remain.
Spoon the batter into the prepared liners, filling each about two-thirds full.
Bake until the tops look set, then remove the pan and let the brownie bites cool completely.
Place the white chocolate chips in a microwave-safe bowl and heat in short bursts, stirring between each, until melted and smooth.
Spread a small amount of melted white chocolate on each cooled brownie bite.
Press two candy eyeballs into the white chocolate on each bite before it sets.