Pre-heat oven to 350 degrees.
Whisk together flour, baking powder, and salt together in a medium-sized bowl.
In a large bowl with a hand mixer or in the bowl of stand mixer, mix butter and both sugars at medium speed until light and fluffy, 2-3 minutes.
Mix in eggs, vanilla, and mushed banana until well-blended.
Add flour mixture to bowl and mix until just combined, taking care not to over-mix.
Fold in freeze-dried strawberries and rainbow sprinkles.
Drop rounded tablespoon-sized scoops of cookie dough onto parchment paper-lined cookie sheets about 2 inches apart.
Bake at 350 degrees for 12-15 minutes, until edges are just turning golden.
Remove from oven and place cookies on wire racks to cool completely.
Once cooled, drop teaspoonfuls of marshmallow sauce or chocolate sauce onto cookies and top with additional sprinkles and a maraschino cherry.