Pour 2 cups of heavy cream and 1 ½ tsp vanilla (or maple) extract into a large mixing bowl or stand mixer.
Using hand mixer / electric mixer or whipping attachment for stand mixer, beat cream on medium-low speed for 1 minute.
Increase to medium speed and beat 1 additional minute. Increase to high speed and beat just until relatively stiff peaks start to form. Do not over beat.
In a separate medium bowl, stir together sweetened condensed milk and pecan butter. Fold the whipped cream into the pecan butter mixture with a rubber or silicone spatula. Fold just until combined. Don't over mix. Add ½ cup pecan pieces and mix pecans in gently.
Pour ice cream mixture into a 9- x 5-inch loaf pan or 8- x 8-inch square pan. Sprinkle the remaining ¼ cup pecan pieces in a single layer over the top.
Cover ice cream with plastic wrap. Then wrap with aluminum foil to create an air-tight container. Freeze at least 4 hours or until finished ice cream is firm enough to scoop.