Preheat oven to 350°F (175°C).
Grease a Bundt pan or 9x13" baking dish with butter or non-stick spray.
Cut each biscuit into 4 pieces.
In a bowl, mix granulated sugar and cinnamon.
Roll each dough piece in the cinnamon-sugar mixture until coated.
Arrange half the dough pieces in the pan.
Sprinkle with ½ of the nuts (if using).
Repeat with remaining dough and nuts.
In a saucepan, melt butter, then stir in brown sugar and vanilla.
Pour evenly over the dough.
Bake for 30–35 minutes until golden and bubbly.
Let cool 5–10 minutes, then invert onto a plate.
Pull apart while warm and enjoy!
