Line a 13 x 9 inch pan with parchment paper.
Heat a large pot over medium heat. Add butter to pot and melt. Once butter is melted add marshmallows to the pot.
Stir marshmallows until melted and remove from heat.
Stir in vanilla extract and rice cereal. Gently stir the cereal into marshmallow mixture is coated. Spread evenly into prepared pan without pressing too firmly.
Allow the rice krispie treats to cool at room temperature for an hour before cutting.
Use the parchment as handles to remove from the pan and transfer to a cutting board. Cut into 20 square bars.
If using the lollipop sticks, insert into one end, being careful to not go all the way through. Place the bars into the freezer to firm around the stick for a few minutes while you melt the chocolate.
Place chocolate chips in microwave safe bowl and microwave for 60-90 seconds, stirring every 15 seconds until the chocolate is melted and smooth.
Dip the bars into the melted chocolate. Use a knife to evenly coat the sides and scrape off any excess chocolate. Lay on parchment paper to harden. Decorate with sprinkles or icing.
Store treats in an airtight container at room temperature for 2-3 days.