Preheat the oven to 350 degrees F. Butter and flour a bundt cake pan.
In the bowl of a mixer, beat butter and brown sugar until light and creamy. Add eggs one at a time, then vanilla.
In a separate bowl, whisk together flour, baking powder, baking soda, and salt. With the mixer running, alternate adding caramel liquid and dry ingredients until just combined.
Pour into the prepared pan and bake until a toothpick comes out clean, about 45-55 minutes. Let cool in pan 10 minutes, then invert onto a wire rack to cool completely.
Frosting
Beat butter, powdered sugar, vanilla, and caramel liquid until smooth. Adjust consistency with extra caramel liquid if needed.
Frost the cooled cake and store in an airtight container at room temperature.
Notes
Caramel bundt cake with a rich caramel glaze makes a perfect autumn dessert. Store covered at room temperature for up to 4 days.