1. Preheat oven to 300 degrees F. Line 2 large cookie sheets with parchment paper; set aside.
2. Combine the almonds and powdered sugar in the bowl of a food processor. Cover and pulse until very finely ground; set aside.
3. Beat the egg whites and salt in a large bowl with an electric mixer on medium speed until foamy. Increase speed to high and add the granulated sugar 1 tablespoon at a time, beating well after each addition. Beat until soft peaks form and egg whites are light and glossy.
4. Use a rubber spatula to fold half of the almond mixture into the egg whites until blended. Add the vanilla, food coloring, and remaining half of the almond mixture and fold until blended.
5. Spoon the mixture into a pastry bag fitted with a coupler or a large resealable plastic bag and snip a 1/4-inch hole in one corner.
6. Pipe 1 1/4-inch mounds onto the prepared cookie sheets about 1 1/2 inches apart. Bake, rotating the sheets halfway through, until firm and just starting to brown lightly, about 15 minutes. Transfer the pans to a wire rack and cool 5 minutes.
7. Use a metal spatula to remove the macaroons from the pans and cool completely.
8. When cool, spread strawberry preserves on a flat side of half of the cookies. Top with remaining cookies, flat sides down.