Begin by lining a muffin tin with cupcake liners. You can use a regular-size pan or mini cups. A silicone mold works great too.
In a medium-sized bowl, mix together the peanut butter, melted coconut oil, vanilla, and honey until well combined.
Add the rice crispy cereal to the mixture and stir until evenly incorporated.
Use a tablespoon to scoop heaping tablespoons of the batter into each muffin liner, distributing evenly among 12 liners.
Place the muffin tin in the freezer for at least 20 minutes or until the cups are firm.
For the optional chocolate drizzle, microwave the chocolate chips and coconut oil in a small bowl for 30 seconds to a minute until melted. Stir until smooth.
Once the peanut butter cups are firm, remove them from the freezer and drizzle with the melted chocolate mixture. Sprinkle a bit of sea salt on top.
Store the cups in the freezer for up to 3 months.