Combine the Dr Pepper, hot sauce and brown sugar in a small saucepan over medium-high heat.
Bring to a boil then reduce to a simmer. Let simmer for about 30 minutes or until reduced by half and slightly thickened.
If you want your sauce a little thicker, place the corn starch in a cup, small bowl or glass. Add in 1/4 cup or so of the sauce and stir to combine. Pour into the sauce pan and stir to thicken.
Remove from heat and let cool slightly before serving.