Prepare a macaron template by using a large piping tip or small round cookie cutter of about 1 ½″ in size to trace circles about 2 inches a apart on one sheet of parchment paper. You will place this under another piece of parchment paper when ready to pipe the macaron shells.

In a medium bowl, sift the powdered sugar, almond flour, and spices twice.

Next, heat the egg whites and granulated sugar over a double boiler until the sugar has dissolved or until the temperature is about 120 degrees F.

Transfer the egg white mixture to a large bowl or a bowl of a stand mixer fitted with a whisk attachment. Whisk until the meringue reaches soft peaks. At this point, you can add the vanilla paste.

Continue whisking the meringue until stiff peaks form. The best way to test if it is ready is by turning the bowl upside down. If the meringue does not fall or move at all, then it is ready.

Start the macaronage by folding in ⅓ of the dry ingredients. Mix carefully with a silicone spatula by scraping aroung the sides of the bowl, then through the middle of the batter. Do this a few times until it is mostly combined.

Add the remainder of the dry ingredients, folding with the same gentle method. Once the dry ingredients are fully incorporated, begin spreading the batter along the sides of the bowl to deflate it slightly. I find that this mixing method ensures that the shells do not bake up hollow. Continue scraping around the sides of the bowl and through the middle. The mixture is ready when you can draw several figure eights without the batter breaking.

Transfer the mixture to a piping bag with a small round piping tip (I used Ateco 802). Place your macaron template under another piece of parchment paper on a baking sheet and pipe perpendicular to fill in each circle. Carefully remove the template and tap the baking sheet on the on counter a few times in order to release any air bubbles. It also helps to bang on the bottom of the baking sheet with your hand. 

Let the macarons rest for about 30-40 minutes, or until they are dry and no batter comes away when you touch them. Toward the end of the resting time, preheat the oven to 300 degrees F. Bake the macarons for about 8-12 minutes. Allow to cool completely before removing them from the baking sheet.

Start with the pastry cream – heat the milk in a saucepan, and bring to a simmer or about 200 degrees F.

Whisk the egg yolks, brown sugar, molasses, cornstarch, and spices together for 2-3 minutes until fully combined.

Once the milk is simmering, slowly pour half into the egg-sugar mixture, whisking at the same time to temper the eggs. 

Pour everything back into the saucepan and heat over medium heat, whisking constantly. After a few minutes, it will begin to thicken.

Once it has thickened and large bubbles come to the surface, continue whisking for one more minute, then remove from heat.

Transfer to a bowl and cover with plastic wrap, pressing it directly up against the pastry cream to prevent a skin from forming. Chill overnight. Alternatively, you could place the bowl of pastry cream over a water bath and whisk constantly until it cools down to 70 degrees F - you can immediately turn it into buttercream at this point. 

If the pastry cream was chilled overnight, make the buttercream by beating the pastry cream for about 10 minutes on low speed until it warms up to about 70 degrees. 

Add the vanilla and butter, a few cubes at a time, and beat on medium speed. If it looks curdled at all, continue beating on low speed until smooth.

Transfer the buttercream to a piping bag fitted with a small star tip (I used Ateco #864).

Pair the macaron shells up and pipe the buttercream onto the bottom shell, then place the paired shell on top, pressing down slightly to ensure they stick together.