To make the cupcakes: Preheat oven to 350F/175C. Line muffin tin with cupcake liners. Set aside.
In a medium bowl, sift together flour, baking powder, and salt. Set aside.
In a standing mixer fitted with the paddle attachment, beat together butter and sugar on medium speed until light and fluffy, about 3 minutes. Scrape down the sides and bottom of the bowl occasionally. Beat in eggs one at a time, beating well after each addition. Add mashed bananas and vanilla extract and beat. With the mixer on low speed, add half of the flour mixture, followed by the milk, then add the rest of the flour mixture and beat just until combined. Do not overmix—the less you mix, the lighter the cupcakes will be. Fold in chocolate chips.
Divide batter evenly between muffin cups, filling them about ¾ full. Bake for 15-20 minutes until a toothpick inserted into the center comes out clean or with just a few moist crumbs. Allow cupcakes to cool for 10 minutes, then remove from pan and allow them to cool completely on a wire rack.
Fill the cupcakes: Core each cupcake with a cupcake or apple corer, or use a teaspoon to scoop out holes, leaving a well in the center of the cupcake. Place dulce de leche in a a pastry bag, cut off the corner of the bag, and fill the holes (or just use a teaspoon to fill it instead).
To make the frosting: In a mixer bowl, place heavy cream, cheese, sugar, and vanilla. Beat until soft peaks form. Add banana puree and beat just until stiff peaks form and mixture is smooth. Don’t overbeat so it won’t become grainy. Frost cupcakes immediately after making the frosting. Decorate with banana chips or crushed cookies if desired.
Cupcakes can be kept tightly covered in the refrigerator for up to 4 days.Unfrosted cupcakes can be kept tightly covered at room temperature for up to 3 days, or in the freezer for up to 2 months. Thaw, still covered, on the counter or overnight in the fridge.