Preheat oven to 350F (175C). Grease and flour an 8-inch round cake pan.
In a medium bowl, whisk together the gluten-free flour, baking powder, baking soda, and salt.
In a large bowl, cream together the softened butter and sugar until light and fluffy.
Beat in the eggs one at a time, then stir in the vanilla extract. If using food coloring, add it now.
Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined.
Gently fold in the chopped strawberries.
Pour the batter into the prepared cake pan and spread evenly.
Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean.
Let the cake cool in the pan for 10 minutes before inverting it onto a wire rack to cool completely.
Slice the cooled cake into even pieces.
Arrange the slices on freeze-dryer trays, ensuring they are not touching.
Freeze-dry according to the manufacturer's instructions for your freeze-dryer (typically 24-48 hours).
Store the freeze-dried cake slices in an airtight container to maintain crispness.
Tip: For a stronger strawberry flavor, add 1/2 teaspoon of strawberry extract to the batter. Almond flour can be substituted for 1/4 cup of the gluten-free flour for a slightly nutty flavor.