Preheat your oven to 350°F. Line a large sheet pan with parchment paper or a silicone baking mat and set aside.
In a large bowl, combine the flour, oats, brown sugar, baking soda, and salt. Stir well to ensure everything is mixed evenly.
Melt the butter and let it cool to room temperature. It’s important to cool it so it doesn’t melt the sugar and create greasy cookies. Once cooled, combine the melted butter with the vanilla extract and the egg.
Pour the wet ingredients into the dry ingredients and stir until a thick dough forms. If necessary, knead the mixture with your hands to ensure everything is combined.
Cover the dough and refrigerate while you unwrap the Rolos. This helps firm up the dough a bit.
Take about 3 tablespoons of dough and flatten it in your hand. Place two Rolos in the center, then fold the edges of the dough up around the candies. Make sure to seal them completely, as you don’t want any candies exposed.
Place 6 to 8 cookies on the prepared sheet pan, leaving enough room between them. Refrigerate for 10 minutes to help them firm up before baking.
Bake for 9 to 12 minutes. I love to underbake them slightly to keep them soft and gooey. If you overbake, the caramel will turn hard.
Once done, let the cookies sit on the sheet for 2 to 3 minutes, then transfer them to a cooling rack to firm up further.
To top with chocolate, combine the chocolate chips and vegetable oil in a microwave-safe bowl. Microwave in bursts of 15 seconds, stirring in between until fully melted.
Drizzle the melted chocolate over the cooled cookies or transfer the melted chocolate to a small plastic bag, snip the tip off, and drizzle it over the cookies.