Prepare a baking sheet by lining it with parchment paper. Place half of the Ritz crackers on the sheet with the salty side facing up.
Spoon a generous amount of peanut butter, about 1 tablespoon, onto each cracker. Top with another cracker, salty side down to make sandwiches, and gently press them together.
Refrigerate the assembled sandwiches for 10–15 minutes to firm up the peanut butter filling.
In a microwave-safe bowl, melt the chocolate chips in short bursts, stirring every 30 seconds until smooth. If using, add vanilla extract and mix well.
Once melted, dip each peanut butter sandwich into the chocolate mixture, ensuring it's fully coated. Use a fork to lift it out, gently tapping to remove excess chocolate before placing it back on the baking sheet.
Sprinkle chopped nuts or cocoa powder immediately after dipping while the chocolate is still wet. Repeat the process until all sandwiches are coated.
Allow the chocolate to set at room temperature for about 20 minutes or refrigerate to speed up the hardening process before enjoying your cookies.