Preheat the oven to 350 degrees F.
Line an 8×8-inch baking pan with parchment paper. Set aside.
In a large saucepan (with a lid) bring 6 cups of water to a boil.
Add the steel-cut oats to the boiling water. Cover and reduce the heat to a gentle simmer and cook for 10 minutes.
Drain the oats; rid of as much water as possible.
Set aside to cool for approx. 10-15 minutes.
In a large mixing bowl combine flour, brown sugar, cinnamon, baking soda, and salt. Stir thoroughly to ensure it's evenly mixed.
Add the cooked oats, coconut oil, eggs, and vanilla. Mix until the the ingredients are well combined. The batter will be very thick and moist - this is the consistency you're looking for.
Add the dates and walnuts and, with a spatula, gently fold them into the mix.
Scoop the dough into the prepared baking pan and use a spatula to flatten the dough into an even surface.
Bake at for 30-35 minutes.
Let the bars cool completely before cutting them or removing them from the pan.
Once cooled, you may remove the cake, spread the glaze on it, and cut into even portions.