Preheat the oven to 350°F (175°C).
In a large mixing bowl, combine 1 cup creamy peanut butter, granulated sugar, and light brown sugar. Mix until smooth and creamy.
Add the egg and 1 teaspoon vanilla extract to the peanut butter mixture and beat until fully incorporated.
In a separate bowl, whisk together 1/2 teaspoon baking soda, 1/4 teaspoon salt, and 1 cup all-purpose flour.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined to form a dough.
Press the dough evenly into a 12-inch round pizza pan or a rimmed baking sheet to form the cookie crust.
Bake in the preheated oven for 12 to 15 minutes, or until the edges are lightly golden and the center is set.
Remove the cookie crust from the oven and allow it to cool completely in the pan on a wire rack.
While the crust cools, prepare the frosting by beating together 4 ounces softened cream cheese, 1/4 cup creamy peanut butter, 1/4 cup powdered sugar, and 1/2 teaspoon vanilla extract until smooth and creamy.
Once the cookie crust is completely cooled, spread the peanut butter cream cheese frosting evenly over the top.
Arrange the sliced strawberries, blueberries, kiwi, mandarin orange segments, and halved red grapes decoratively over the frosting.
Slice the peanut butter cookie fruit pizza into 8 wedges and serve immediately or refrigerate until ready to serve.