01 - Line a large baking sheet with parchment paper or a silicone baking mat to prevent sticking.
02 - In a large bowl, combine Rice Krispies cereal, mini marshmallows, and pecans if using. Mix well and set aside.
03 - In a medium saucepan over medium heat, melt butter. Add brown sugar, brewed coffee, espresso powder, and salt. Stir constantly until the mixture is smooth and just begins to bubble, about 2-3 minutes. Remove from heat and stir in vanilla extract.
04 - Pour the hot coffee mixture over the cereal mixture. Quickly fold with a spatula until all ingredients are evenly coated with the coffee syrup.
05 - Using a cookie scoop or tablespoon, drop mounds of the mixture onto the prepared baking sheet. Press gently with your fingers to shape into round cookies if needed.
06 - If desired, melt chocolate chips with coconut oil in a microwave-safe bowl in 20-second increments, stirring until smooth. Drizzle over the cookies using a fork or spoon.
07 - Place the baking sheet in the refrigerator and chill for at least 30 minutes or until the cookies are firm and set.
08 - Transfer cookies to an airtight container and store in the refrigerator for up to 1 week for best texture and flavor.