Step 1: Line a 12-cup muffin tin with paper liners. Set aside.
Step 2: In a medium bowl, combine the finely crushed vanilla wafers and granulated sugar. Pour in the melted butter and mix until all crumbs are moistened.
Step 3: Divide the crumb mixture evenly among the 12 muffin cups. Press firmly into the bottom of each liner to form the crust. Place the muffin tin in the refrigerator to chill while you prepare the filling.
Step 4: In a large mixing bowl, beat the softened cream cheese with an electric mixer until smooth and creamy. Add the sifted powdered sugar and vanilla extract, beating until well combined and lump-free.
Step 5: Gently fold in the mashed banana into the cream cheese mixture until just combined.
Step 6: In a separate chilled bowl, whip the heavy cream with an electric mixer on medium-high speed until stiff peaks form.
Step 7: Gently fold the whipped cream into the banana cream cheese mixture using a spatula, being careful not to deflate the cream. Mix until just combined and light.
Step 8: Spoon the cheesecake filling evenly over the chilled crusts in the muffin tin. Smooth the tops with a spoon or offset spatula.
Step 9: Refrigerate the mini cheesecakes for at least 2 hours, or preferably overnight, until firm.
Step 10: Before serving, carefully remove the cheesecakes from the muffin liners. Garnish each cheesecake with fresh banana slices and a dollop of extra whipped cream. You can also add a small vanilla wafer for a decorative touch. Serve immediately and enjoy!