In the bowl of a stand mixer fitted with the paddle attachment, beat together butter, brown sugar, and oil at medium speed until creamy, 3 to 4 minutes, stopping to scrape sides of bowl. With mixer at low speed, add golden syrup, egg, and vanilla, beating until combined. Scrape sides of bowl.
In a medium bowl, whisk together flour, baking soda, salt, cinnamon, and cloves. Gradually add flour mixture to butter mixture, beating just until combined. Turn out dough onto a lightly floured surface, and shape into a disk. Wrap tightly in plastic wrap, and refrigerate for at least 30 minutes.
Preheat oven to 375°. Line a baking sheet with parchment paper.
Place oats in a shallow bowl. Using a 1¾-teaspoon scoop, scoop dough, and roll into balls. Roll balls in oats, coating completely. Place on prepared baking sheet.
Bake for 10 minutes. Let cool completely on a wire rack. Store in an airtight container at room temperature for up to 3 days.
Recipe by TeaTime Magazine at https://teatimemagazine.com/treacle-oatmeal-cookies/