Preheat oven to 350°F and cut parchment paper into 12 5x5-inch squares. Press each sheet of parchment paper into the well of a muffin tin. Use a cup to press down and rotate to help shape the parchment. The parchment will puff out of the pan until ingredients are added to it.
Roll out one crescent roll sheet on a clean surface (I like to do it on a sheet of parchment paper). Melt 2 tablespoons of salted butter and brush the dough with it, leaving a ½-inch border at one of the short ends. There should be enough for the second dough, using about 1 tablespoon each.
Combine 3 tablespoons salted butter, 1 cup light brown sugar, 2 teaspoons ground cinnamon, and 1 teaspoon vanilla extract in a small bowl and sprinkle half of the mixture evenly over the buttered dough. Spread and pat it down so it covers as evenly as possible. Making sure to leave the same border on the short end that you did with the butter.
Use a pastry or pizza cutter to cut the dough into 6 strips starting from the short end so they are long. Roll each strip up, so that they roll with the border end sealing the roll up, and repeat for the other sheet of crescent roll dough.
Add 1½ teaspoons of pecan pieces and 1 teaspoon heavy cream to each muffin liner and then place a roll in each one.
Bake for 20 to 23 minutes until bubbly in the creases and the rolls don't wiggle too much. You want tops to be a golden brown and the centers should read 200°F on an instant-read thermometer.
Remove from oven and let cool on the pan for 15 to 20 minutes.
Whisk together 1 cup powdered sugar 6 tablespoons heavy cream, and 1 teaspoon vanilla extract until desired consistency is reached, spread over cooled, but slightly warm, cinnamon rolls and sprinkle with additional pecans if desired.