Preheat oven to 350.

Whisk together flour, baking soda, salt, and espresso powder.

In a separate bowl, mix butter and 1 ½ cups sugar on medium-high speed until light and fluffy (2-3 minutes). Add egg and vanilla extract. Combine until smooth.

Gradually add the flour mixture to the butter and sugar mixture.

Make 1 Tbsp balls of batter. I use a 1-inch cookie scoop and cut those balls in half for consistency. Place your cookie balls onto lined baking sheets, spaced two inches apart as they will spread during baking.

Cook for 11-13 minutes. They will still seem soft.

Cool completely.

Add semi-sweet chocolate and cubed butter to the top pan or dish and place over the steaming water.

Stir the mixture occasionally until completely melted and glossy.

Remove from heat and allow to cool slightly. Should still be smooth and glossy, but a little thicker.

Set aside while making the buttercream. If the mixture gets too thick, simply reheat using the same melting method.

In the bowl of a stand mixer fitted with the whisk attachment, add the egg yolks. Beat for 6 minutes on medium-high speed. The mixture will look thick and have a pale yellow appearance.

While the yolks are being whipped, combine the sugar and the 3 tablespoons of water in a medium saucepan and place over medium-high heat. Swirl occasionally until the sugar is dissolved.

Add 4 Tbsp of Kahlua.

Insert candy thermometer, and bring to a boil. Continue boiling the sugar-Kahlua mixture until it reaches 240F. Immediately remove from the heat.

With the mixer running, carefully and slowly pour the sugar syrup into the egg yolks in a steady stream. Small beads of sugar crystals may splatter onto the side of the bowl and harden. That's OK. Just ignore them.

Beat mixture on medium-high speed until very stiff, about 10 minutes.

Decrease the speed to medium and add the room-temperature butter, a tablespoon at a time, waiting a few seconds between each addition.

Add 2 more Tablespoons of Kahlua.

Beat on medium-high speed for about 3-5 minutes until thick and pipeable.

Spoon a small amount of chocolate ganache onto the espresso cookie. This is a thin layer that just covers the cookie. Spread on top of the cookie, leaving a small rim around the edge.

Add buttercream into a piping bag fitted with a 1M piping tip.

Creating a beautiful rose design is easier than it looks. Hold the piping bag perpendicular to the cookie. Simply start in the center of the cookie and move in a circle motion working out to the edge of the chocolate ganache. See video tutorial.