Prepare the baking sheet: Line a large rimmed baking sheet or tray with parchment paper. Make enough room in the refrigerator or freezer for the tray to sit flat.

Grind the oats: Add the rolled oats to a food processor. Process for 30 to 45 seconds, until they resemble a coarse flour with only a few small oat pieces remaining.

Mix the base: Transfer the ground oats to a medium mixing bowl. Add the peanut butter, honey, vanilla, and salt. Stir until the mixture is thick, evenly moistened, and holds together when pressed.

Add the Butterfinger candy: Fold in the 1 cup (140 g) crushed Butterfinger candy. The filling should remain soft but scoopable, with small crisp candy pieces distributed throughout.

Adjust the consistency if necessary: If the mixture feels too sticky to shape, refrigerate it for 10 minutes before adding anything else. If it is still very soft, mix in 1 tablespoon of additional ground oats at a time. Avoid making the filling dry or crumbly.

Shape the bliss balls: Scoop approximately 1 tablespoon of filling at a time and roll gently between your palms into a ball about 1 1/4 inches (3 cm) wide. Arrange the balls on the prepared tray. You should have about 24.

Chill until firm: Refrigerate the shaped balls for 30 minutes, or freeze for about 15 minutes. They should feel firm enough to lift without losing their shape but should not be frozen solid.

Melt the chocolate: Place the chopped semisweet chocolate and coconut oil in a microwave-safe bowl. Microwave in 20-second intervals, stirring thoroughly after each interval, until nearly melted. Stir until completely smooth. Alternatively, melt gently over a double boiler.

Coat the first ball: Drop one chilled ball into the melted chocolate. Turn it with a fork until fully coated, then lift it out and tap the fork gently against the bowl so excess chocolate drips away.

Transfer and decorate: Place the coated ball back on the parchment-lined tray. Immediately sprinkle with some of the optional crushed Butterfinger candy before the chocolate begins to set.

Coat the remaining balls: Repeat with the remaining filling. If the chocolate thickens, warm it briefly for 10 seconds and stir. If the uncoated balls become very soft, return them to the refrigerator for a few minutes.

Chill to set the coating: Refrigerate the coated bliss balls for at least 45 minutes, until the chocolate is completely firm and releases cleanly from the parchment.

Serve chilled or slightly softened: Serve directly from the refrigerator for a firm center, or let the bliss balls stand at room temperature for 5 to 10 minutes for a softer, chewier texture.