Add chopped dates to a heatproof bowl. Pour in boiling water, stir in baking soda, and let sit 10–15 minutes. Lightly mash into a thick paste.
Preheat oven to 350 °F (175 °C). Grease or line an 8×8-inch pan with parchment.
Whisk eggs, honey, melted coconut oil, and vanilla. Stir in the softened date paste.
In another bowl, whisk flour, cinnamon, nutmeg, salt, and baking powder.
Gently fold dry mix into wet batter. Stir in walnuts, reserving some for topping.
Spread batter in pan, top with reserved walnuts. Bake 30–35 minutes, or until a toothpick comes out clean or with moist crumbs.
Cool in pan 10–15 minutes, then transfer to a rack. Drizzle with honey or maple syrup and add extra walnuts if desired. Slice and serve.