- Preheat oven to 350F (175C). Grease and flour a 9x13 inch baking pan. 
- In a medium bowl, whisk together flour, baking powder, and salt. 
- In a large bowl, cream together butter and sugar until light and fluffy. Beat in eggs one at a time, then stir in vanilla. 
- Gradually add dry ingredients to wet ingredients, alternating with milk, beginning and ending with dry ingredients. Mix until just combined. 
- Stir in cup freeze-dried strawberry powder. 
- Pour batter into prepared pan and bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean. 
- Let cake cool in pan for 10 minutes before inverting onto a wire rack to cool completely. 
- While the cake cools, prepare the frosting: In a large bowl, cream together butter and powdered sugar until smooth. 
- Beat in freeze-dried strawberry powder, milk, and vanilla extract until light and fluffy. Add more milk if needed to reach desired consistency. 
- Once the cake is completely cool, frost the cake. Decorate with whole freeze-dried strawberries and/or a sprinkling of freeze-dried strawberry powder, if desired. 
- For a gluten-free option, substitute all-purpose flour with a gluten-free all-purpose flour blend. Ensure all other ingredients are also gluten-free. For a more intense strawberry flavor, increase the amount of freeze-dried strawberry powder in both the cake and the frosting. For a vegan option, substitute butter with vegan butter, eggs with flax eggs, and milk with plant-based milk.