Preheat the oven to 350°F. Grease a 12-inch pizza pan or a large baking sheet.
In a large bowl, combine the flour, granulated sugar, baking powder, and salt. Add the softened butter, egg, and vanilla extract. Mix until a dough forms.
Press the dough evenly into the prepared pizza pan. Bake for 12-15 minutes, or until lightly golden. Remove from the oven and let cool completely.
In another bowl, beat the softened cream cheese, powdered sugar, and vanilla extract until smooth and creamy.
Spread the cream cheese mixture evenly over the cooled cookie crust.
In a separate bowl, toss the sliced bananas with lemon juice to prevent browning. Arrange the strawberries, blueberries, and bananas on top of the cream cheese layer in a decorative pattern.
Slice and serve immediately, or refrigerate for up to 2 hours before serving for a chilled treat.