Line a 9×13 inch baking dish with criss-crossed parchment paper. A metal dish will produce a more evenly crisp bar bottom. You could also use a jelly roll pan.
Make bars:
Preheat the oven to 300°F.
In the bowl of a stand mixer or with a hand mixer, cream the butter. Add the sugar and cinnamon and beat to mix well. Beat in the egg yolk, but reserve the white.
Reduce your mixer speed to low and gradually add the flour and salt. Mix until combined.
Press your dough into the bottom of the prepared baking dish. You will want to spread and press the dough into the dish with your hands, and try to get it as even as possible. {But don’t try too hard. No one will see.}
In a small bowl, beat or whisk the egg white until it is foamy. Use a pastry brush to brush the top of the dough with the whisked egg white. Spread all the almonds over the top of the egg white. Press them down a little so they will slightly adhere.
Bake the bars in the preheated oven until golden brown. Mine took about 30 minutes. A minute or so before removing the bars from the oven, mix the glaze.
Make the glaze:
In a bowl, whisk together the melted butter, water, lemon juice, and confectioner’s sugar.
Assemble & enjoy:
Drizzle the glaze over the top of the warm bars! You can spread it evenly with an offset spatula if it pools in areas.
Cool the bars for 20-25 minutes and then cut them into pieces. I find a serrated knife useful here. Allow your bars to cool completely on a wire rack, and enjoy!
Notes
Presentation - Let the bar cookies cool slightly before cutting with a serrated knife for a clean edge!Flavor Tips - Lemon juice is the flavor in your glaze, so try to use the freshest lemon juice possible.Technique - Keep the glaze moving so it doesn’t pool. One way to do this is to create a pattern like a sine wave, and then go back across in the same pattern, filling in the gaps. Helpful Tools - Lining your pan with parchment paper is a key detail to help remove the bars from the pan easily!Variations - You can easily modify these bar cookies to your tastes! Use different nuts or a different spice mix–whatever you desire, as long as the ratio remains relatively the same.Storage - Store these bar cookies in an air-tight container at room temperature or frozen. These will keep 2 weeks at room temperature or 2 months frozen.