Preheat oven to 350 degrees Fahrenheit. Line 2 baking sheets with parchment paper.
In a large bowl, combine melted butter, maple sugar, egg, and vanilla then whisk until smooth.
In a small bowl, mix together flour, baking soda, and salt. Add to butter mixture and mix well. Mix in dates and oats and combine thoroughly.
Roll rounded tablespoons of mixture into balls and place on baking sheets. Bake until golden brown, rotating sheets halfway through, approximately 18 to 20 minutes.
Date cookies will stay fresh in an air tight container for 1 week or freeze for up to 3 months.