01 - Preheat oven to 350°F and line two baking sheets with parchment paper.
02 - Combine chopped dates and boiling water in a small bowl. Stir in baking soda and let stand for 10 minutes to soften.
03 - Beat butter, brown sugar, and granulated sugar in a large bowl until light and fluffy.
04 - Mix in egg and vanilla extract until fully incorporated.
05 - Whisk together flour, baking powder, and salt in a separate bowl.
06 - Add dry ingredients to wet mixture and stir until just combined. Fold in softened date mixture including all liquid.
07 - Drop tablespoon-sized dough portions onto prepared baking sheets, spacing 2 inches apart.
08 - Bake for 10 to 12 minutes until edges are set and centers appear slightly underbaked. Cool on pan for 5 minutes, then transfer to wire rack.
09 - Melt butter and brown sugar in a small saucepan over medium heat, stirring until dissolved. Add heavy cream and salt, bring to simmer, and cook for 1 to 2 minutes until thickened. Remove from heat and stir in vanilla.
10 - Drizzle warm toffee glaze over cooled cookies. Allow glaze to set before serving.