Preheat your oven to 350°F. Line a 9x13-inch baking pan with parchment paper, letting edges overhang slightly for easy removal. This prevents sticking and ensures even browning. (5 minutes prep)

In a medium bowl, whisk together 1 3/4 cups all-purpose flour, 3/4 cup unsweetened cocoa powder, 1 teaspoon baking soda, and 1/2 teaspoon salt. Set aside. (3 minutes)

In a small saucepan or microwave-safe bowl, combine 1/2 cup unsalted butter and 8 ounces chopped semi-sweet chocolate. Heat over low heat or microwave in 30-second intervals, stirring between each interval, until completely melted and smooth. (5 minutes)

In a large mixing bowl, combine the chocolate mixture with 1 cup granulated sugar and 1/2 cup packed brown sugar. Stir well with a spatula or wooden spoon. (2 minutes)

Add 3 large eggs one at a time to the chocolate mixture, stirring well after each addition until fully incorporated. (2 minutes)

Stir in 2 teaspoons vanilla extract, 2 mashed ripe bananas, and 1/4 cup sour cream. Mix until the banana is fully incorporated and the batter is smooth. (3 minutes) Checkpoint: Your batter should be thick, glossy, and uniform in color with no streaks.

Gently fold the dry ingredients into the wet mixture using a spatula. Fold in slow, deliberate strokes until just combined—do not overmix or the brownies will be tough. Stop as soon as no dry flour is visible. (2 minutes)

Pour the batter into the prepared pan, spreading it evenly into all corners with an offset spatula or the back of a spoon. (2 minutes)

Place the pan on the center oven rack and bake for 20–25 minutes. The brownies are done when a toothpick inserted in the center comes out with a few moist crumbs (not wet batter). The top should look slightly set but still tender. (25 minutes at 350°F) Checkpoint: The edges should pull slightly away from the pan sides, and the center should jiggle only slightly when gently shaken.

Remove the pan from the oven and let the brownies cool to room temperature on a wire rack, about 45 minutes. Then refrigerate for at least 1 hour (or up to 4 hours) to make frosting easier. (60 minutes total)

While brownies chill, prepare the banana pudding layer. In a medium bowl, whisk 1 cup instant vanilla pudding mix with 1 1/2 cups cold whole milk according to the pudding package directions, stirring constantly. Let sit for 2 minutes until thickened. (3 minutes)

In a separate bowl, beat 8 ounces softened cream cheese with an electric mixer on medium speed until smooth and creamy, about 1–2 minutes. (2 minutes)

Add 1/4 cup powdered sugar and 1 teaspoon vanilla extract to the cream cheese. Beat on low speed until combined. (1 minute)

Gently fold the thickened pudding into the cream cheese mixture using a rubber spatula with slow, deliberate strokes until no streaks remain. Do not overmix. (2 minutes) Checkpoint: The pudding layer should be smooth, creamy, and light in color with uniform texture.

Remove the chilled brownies from the refrigerator. Spread the pudding mixture evenly over the top using an offset spatula or the back of a spoon, working gently to avoid disturbing the brownie layer below. (3 minutes)

Refrigerate the brownie-pudding combination for 30 minutes to allow the pudding layer to set slightly. (30 minutes)

While the pudding sets, prepare the vanilla cream topping. In a chilled mixing bowl, pour 1/2 cup heavy whipping cream and add 2 tablespoons granulated sugar. (1 minute)

Using an electric mixer or whisk, beat the cream on medium-high speed for 3–4 minutes until stiff peaks form. Stiff peaks mean the cream stands upright when beaters are lifted. Stop before it turns to butter. (4 minutes) Checkpoint: Peaks should hold their shape and look glossy and smooth.

Remove the brownies from the refrigerator and spread or pipe the whipped cream evenly over the pudding layer. Use an offset spatula for a rustic look or a piping bag for a fancier presentation. (5 minutes)

Crush 1 cup vanilla wafer cookies into coarse crumbs and sprinkle generously over the whipped cream layer, sprinkling extra around the edges for visual appeal. (2 minutes)

Arrange fresh banana slices on top just before serving, pressing them gently into the whipped cream. Serve within 2 hours of topping to keep everything fresh and prevent the banana from browning. (3 minutes)

To serve, cut into squares using a sharp, wet knife, wiping the blade between cuts. Each square should reveal distinct brownie, pudding, and cream layers. (5 minutes)