Preheat the oven to 350°F and line 2 baking sheets with parchment paper or silicone baking mats.
In a medium saucepan, combine the butter, brown sugar, granulated sugar, and honey over medium heat and cook, whisking, until bubbling and the sugar is dissolved, about 5 minutes. Pour the mixture into a large heatproof bowl and whisk in the vanilla, cinnamon, and salt. Let cool until warm (not hot), about 20 minutes.
Add the egg, whisking until smooth. Stir in the oats and flour.
Scoop 1-tablespoon mounds of dough on the prepared baking sheets, spacing them 3 inches apart. Bake, rotating the pans halfway through, until golden brown around the edges, 10 to 12 minutes. Let cool for 5 minutes on the baking sheets before carefully transferring to a rack to cool completely, about 15 minutes. Let the baking sheets cool, then repeat with the remaining dough.
When the cookies are cooled, place the chocolate in a medium microwave-safe bowl and microwave until melted, stirring every 15 seconds. Drizzle the cooled cookies with the chocolate. Alternatively, spread a small amount of chocolate on the underside of a cookie, then place another cookie on top, sandwiching the chocolate in between. Let the chocolate set before serving, about 1 hour.
