Place your dry ingredients (almond flour, powdered sugar, and salt) into your food processor. Process for 5-second increments, three times. Shake the container as needed to ensure even mixing.
Place your strainer over a large bowl.
Sift the almond flour mixture to remove any large bits of almond. If you have to remove a lot, make sure to add the same amount of almond flour back in so that your batter ratio is not thrown off.
Place your egg whites, cream of tartar, and meringue powder into the bowl of your stand mixer with the whisk attachment attached.
Begin whisking your egg whites on medium speed until you reach soft peaks. Medium speed will produce smaller, stronger air bubbles than whipping at high speed.
Sprinkle in the granulated sugar slowly until it's all added and continue whisking on medium until you reach stiff peaks.
Finally, add the vanilla and mix until combined.
Add your meringue to the dry ingredients and begin using the "J fold" method by making a line down the center of your mixture with the rubber spatula and then up and to the left of the bowl. Rotate the bowl 90º and repeat this "J fold" for 10 strokes.
Add your food coloring in at this point. Remember, a little goes a long way. Fold two more times.
Begin testing your batter after stroke 12 for readiness by lifting the spatula out of the bowl to see how the batter runs off the spatula. If the batter stays clumped or does not fall off the spatula, fold it one more time and test again.
Repeat this process until the batter falls off the spatula in a "V" shape. Another test you can do is to firmly bang your bowl onto the counter to see if the batter settles into itself. If it does, it's ready. If it doesn't move it still needs more mixing. Some pastry chefs recommend making a figure 8 with the batter to test readiness but I find this often causes overmixing so looking for the "V" is a safer option.
Prepare your piping bag with a ½" round piping tip by cutting the end of the piping bag off and inserting the tip into the bag.
Twist the piping tip and bag together to seal the bottom of the piping bag and then press the bag into the tip so that the filling does not leak out of the piping bag.
Fold the top of the piping bag down over your hand and scoop the macaron batter into the piping bag with a rubber spatula. Or you can place the piping bag into a tall glass so both your hands are free.
Lay the bag flat on the counter and push all the batter to the bottom of the piping bag so there are no air bubbles and then twist the top to prevent leaking. Tie the top into a knot if desired.
When ready to pipe, pull the piping tip out and move the batter down into the piping tip by squeezing the batter gently. Pro-tip: When you are not piping, hold the piping bag straight up to prevent leaking. When ready to pipe turn the bag over and immediately begin piping.