Mix granulated sugar, cinnamon, and salt in large plastic bag until thoroughly combined.
Cut each biscuit into six even pieces.
Add biscuits to sugar mixture in plastic bag. Coat each biscuit with mixture.
Place 6-7 pieces biscuit into each muffin cup. Set aside.
Melt butter and mix in brown sugar and vanilla. Bring to a boil and lower heat. Cook for 2 minutes on low simmer while stirring.
Spoon 1 Tablespoon of butter mixture over each muffin. If you have left over butter mixture, evenly distribute excess over muffins. Gently move biscuits around so that butter covers more than just the top.
Bake for 15-20 minutes or until biscuits are puffed up and golden brown. Remove from oven.
When cool enough to touch, move muffins out of pan and onto cooling rack.
Recipe by Every Kitchen Tells A Story at https://everykitchentellsastory.com/monkey-bread-muffins/