Preheat oven to 300F

Line packing pans with parchment paper. Do not add any grease.

Beat egg whites until they start to make a foam and then add white sugar and salt. Whip on high until they form a peak that stands upright.

Add food coloring. The recipe advises to add a little more to make the egg whites a shade or two darker, since color fades after baking. I used a little too much of super red gel food coloring. I used Americolor Food Color Super Red.

Mix a little more so the color gets distributed evenly.

Sift almond flour and powdered sugar. You'll get some remains of larger lumps of almond pieces. You need the mixture to be smooth , so you don't get any lumps in the cookies and they don't crack.

Fold almond flour/powder sugar mixture into egg white mixture. Be careful, because if you under mix macarons will be cracked and lumpy and will have no feet. 65-75 turns of your spatula should be the right amount of time.

Transfer batter to a pastry bag.

Using a wide round tip pipe 1 inch rounds on a baking sheet , that you lined with parchment paper.

Tap the pan hard at least 3-5 times to release air bubbles. This will prevent the cookies from cracking.

Let them sit out for between 30 minutes to 1 hour. This will dry them a little before placing them in the hot oven. When they are dry, they can't spread out in the oven and they rise up and form feet.

Bake for 20 minutes. Do not undertake or they will stick to your pan. Some of mine did stick to the parchment paper and it was not easy to separate from it. I recommend that you remove them from the baking sheet in 3-5 minutes after you take them out of the oven.

Whip butter in a mixer until fluffy. Add powder sugar. The original recipe suggests using 3/4 cup of powdered sugar, but it did not seem enough to me, so I used 1 cup powdered sugar. Put strawberries in a food processor/blender and brews a few times. Then set a self over a bowl and run the mixture through to extract the juice. You only need 3 tablespoons of it. Add strawberry juice to the butter cream and whip until well combined. It will take at least a few minutes. Transfer to a pastry bag, fitted with a small tip.

Reverse cookie shells on their backs and pipe small amount of butter cream on one of them. Top with the other shell and you are done. (I've heard that you should not eat them right away , you need to wait for a day, storing them in the fridge, but I can't agree with that. You've come this far making them, so nothing should stop you to try them).