To make the ice cream:
- Peel bananas and slice crosswise into coins. Place in a single layer on parchment-lined baking sheet and freeze for at least 1 hour.
- Combine frozen banana, milk, honey, and vanilla in food processor and process until smooth and creamy, scraping down sides of bowl as necessary. Transfer to freezer-safe container and freeze until ready to use.
To bake the cookies:
- Heat oven to 350°. Line baking sheet with parchment paper.
- Combine flour, baking powder, and salt in medium bowl.
- In a large bowl, use an electric mixer to blend peanut butter, coconut oil, and brown sugar until smooth and fluffy. Stir in flour mixture until thoroughly combined.
- Working in batches, use a tablespoon to form dough into approximate 1-inch balls and place on prepared baking sheet. Gently flatten each ball into a thick disk.
- Bake until edges are browned and bubbling, about 10 minutes. Cool cookies for 10 minutes on baking sheet before transferring to wire rack to cool completely.
- Once all cookies are cooled, melt chocolate in a bowl set over a pot of simmering water.
- Use a teaspoon to spread melted chocolate on the flat side of each cookie and return to parchment-lined baking sheet, chocolate side up. Transfer to freezer to set, about 5 minutes.
To prepare the sandwiches:
- Once chocolate is set, sandwich about 1 heaping tablespoon of ice cream between 2 cookies. Freeze until firm, about 30 minutes.
- For longer storage, wrap ice cream sandwiches in plastic wrap once firm and return to freezer.