Place pitted dates in a bowl and pour warm water over them. Let sit for 10 minutes to soften.
Mash or blend softened dates into a thick paste.
In a bowl, whisk eggs until slightly frothy.
Add melted butter, brown sugar, and vanilla extract, then mix until smooth.
Stir in the date paste until fully combined.
In a separate bowl, mix flour, baking soda, and salt.
Gradually fold dry ingredients into the wet mixture until just combined.
Fold in chopped nuts if using.
Preheat oven to 350°F (175°C) and grease an 8-inch baking pan.
Pour batter into the pan and spread evenly.
Bake for 25 to 30 minutes until a toothpick inserted comes out mostly clean.
Let cool for at least 15 minutes before slicing and serving.