Calypso Bars

Step 1
Preheat oven to 350 degrees F (175 degrees C). Grease an 8×10-inch baking pan.

Step 2
Cook and stir dates, chocolate, water, white sugar, and 1/4 cup butter in a heavy saucepan over medium-low heat until melted and thickened, 5 to 10 minutes. Remove from heat; stir in vanilla extract. Set aside to cool.

Step 3
Beat brown sugar and 3/4 cup butter together in a bowl until creamy. Add oats, flour, walnuts, baking soda, and salt; stir until texture is crumbly.

Step 4
Press half the oat mixture into bottom of the prepared pan. Evenly spread chocolate-date mixture over oat mixture layer; crumble remaining oat mixture over chocolate-date layer.

Step 5
Bake in the preheated oven until topping is lightly browned, about 30 minutes. Cut into 30 small squares.