How to Make It
Heat oven to 325 degrees F. Line two baking sheets with parchment paper and set aside.
Spread the almonds into an even layer and toast in the oven for about 10 minutes, stirring them once to make sure they turn an even golden brown. Remove from heat and transfer almonds to a plate to cool. Lower the oven to 200 degrees F.
Place about half of the almonds into a spice grinder or a food processor and pulse until they are finely ground. Place ¼ cup of the grounds in a small bowl and stir in cornstarch. Set the remaining almonds aside for later.
Add the egg whites and salt to a large, clean, dry bowl. Beat with an electric mixer on medium speed until eggs are frothy and beginning to form soft peaks. Slowly add sugar and rose water and continue beating, increasing speed to medium-high, until egg whites are glossy and stiff peaks form, about 7 minutes. Carefully fold in ground almonds. Add a drop of food coloring and stir gently to combine.
Spoon batter into a large resealable plastic bag. Snip off one small corner of the bag and pipe batter onto the prepared baking sheets in plump 2-inch rounds, leaving 2 inches between each. Top each round with reserved almonds. Bake for 1 hour, then turn off the oven and let meringues cool inside. Remove and cool completely. Serve dusted with confectioner's sugar.