Line a large cookie sheet (or two) with parchment paper.
Place the brown sugar, whipping cream, butter & vanilla in a medium saucepan. Bring to a boil over medium heat, stirring constantly. Boil for about 1 minute, then remove it from the heat. Immediately whisk in the powdered sugar, then gently stir in the pecans.
Allow the mixture to thicken and cool slightly, but it only takes a minute or two.
Drop heaping spoonfuls of the praline mixture onto paper and allow it to cool and set up for at least 30 minutes. You can speed this up by popping the sheet in the frig if you’re impatient like me 😉