In a large bowl, stir creamy peanut butter, softened butter, vanilla extract, and powdered sugar until a smooth, slightly firm dough forms, about 2 minutes of mixing.

Transfer the peanut butter mixture to an 8×8-inch pan lined with parchment paper. Press firmly into an even layer and refrigerate for 15 minutes until set.

In a microwave-safe bowl or over a double boiler, gently melt semi-sweet chocolate chips with shortening (or coconut oil) until smooth and glossy, about 1–2 minutes.

Use a small egg-shaped cookie cutter to stamp shapes from the chilled base. Dip each piece into melted chocolate, coating evenly and letting excess drip off.

Arrange dipped eggs on parchment, sprinkle with colored sprinkles or chopped peanuts, then chill another 10 minutes until the chocolate is fully hardened.