speculoos cookie butter bars

so i didnt think eating the whole jar of trader joes speculoos cookie butter with a spoon was healthy so when i saw this recipe i couldnt wait to try it.  too bad i used salt instead of sugar and had to throw the whole thing out.
Frosted Speculoos Cookie Butter Bars
Makes about 25 small squares
Inspired by this recipe for butterscotch blondies (which is originally from How to Cook Everything)
For the sprinkle:
1 tablespoon (12 grams) sugar
1/2 teaspoon (2 grams) cinnamon
For the cookie bars:
1 1/4 cup (156 grams) flour
1 teaspoon (4 grams) baking powder
1/2 teaspoon (2 grams) baking soda
1/2 teaspoon (2 grams) salt
1/2 teaspoon (2 grams) cinnamon
4 tablespoons (56 grams or half a stick) butter, melted
1/2 cup (110 grams) sugar
1/2 cup (115 grams) brown sugar
1 teaspoon (5 ml) vanilla
2 eggs
1/2 cup (133 grams) speculoos cookie butter*
For the frosting:
2 tablespoons (28 grams) butter, very soft
generous 1/3 cup (about 90 grams) speculoos cookie butter*
2 cups (250 grams) powdered sugar
5 tablespoons (74 ml) half and half or heavy cream, plus more as needed
Make the cookie bars: Preheat the oven to 375. Butter an 8 x 8 pan then line with two sheets of overlapping parchment. In a small bowl mix together the sugar and cinnamon for the sprinkle. Set both aside. In a medium bowl whisk flour, baking powder, baking soda, salt and cinnamon together.
In another medium bowl mix the melted butter with the sugars until combined. Add vanilla and both eggs and mix well until incorporated. Add the cookie butter and stir until smooth and fully combined. Add the flour mixture to the cookie butter mixture and stir to combine. Spread into the prepared pan and smooth the top with an offset spatula.
Sprinkle the cinnamon sugar mixture over the top of the bars and gently tap the pan back and forth so that the sprinkle is evenly spread across the top of the cookies. Bake for 20-25 minutes or until a tester comes out clean. Let cool in the pan for 10 minutes and then transfer to a rack until fully cooled.**
Make the frosting: In a medium bowl beat together the butter, cookie butter and powdered sugar until well combined, then slowly stream the half and half into the powdered sugar mixture. Increase the speed of the mixer and beat the frosting for least 5 minutes, or until light and fluffy. Add a bit more half and half as needed to achieve a spreadable consistency. Generously spread the frosting over the cooled bars. Slice and serve