Step 1: Preheat and Prepare

Start by preheating your oven to 350°F (175°C). This ensures that your cookies bake evenly and are golden brown on the outside while soft on the inside. Line two baking sheets with parchment paper to prevent sticking and make cleanup a breeze.

Step 2: Mix the Wet Ingredients

In a large mixing bowl, place your mashed banana. The banana provides both flavor and moisture to the dough. Use a fork to mash it thoroughly. Next, add in the melted butter, granulated sugar, brown sugar, egg yolk, and vanilla extract. Whisk the ingredients together until fully combined. The mixture will be smooth and slightly glossy, indicating that the sugar has dissolved and the banana is well integrated.

Step 3: Add the Dry Ingredients

Now, it’s time to bring in the dry ingredients! Whisk in the instant vanilla pudding mix, salt, baking soda, and flour. The pudding mix is key to giving these cookies their unique flavor and a little extra richness. Stir until everything is well combined and a dough begins to form. You may notice that the dough is a bit thick, which is perfect for creating a chewy texture in the final cookie.

Step 4: Stir in White Chocolate and Nilla Wafers

For that extra indulgence, fold in the chopped white chocolate and crushed Nilla wafers. The white chocolate adds a creamy sweetness, while the Nilla wafers give the cookies a crunchy, nostalgic element. Be sure to reserve a few pieces of the white chocolate and Nilla wafers to top the cookies before baking.

Step 5: Scoop the Dough

Using a large spoon or a cookie scoop, drop 8 mounds of dough onto your prepared baking sheets. Each mound should be sizable to ensure that the cookies remain soft and chewy in the center after baking. If you like, you can top each mound with the reserved white chocolate chunks and Nilla wafer pieces for extra visual appeal and flavor.

Step 6: Bake the Cookies

Place the baking sheets in the preheated oven and bake for 12 to 15 minutes. The baking time will depend on how soft or crispy you prefer your cookies. For softer cookies, check them at 12 minutes. For firmer, crispier cookies, leave them for the full 15 minutes. At around the 9-minute mark, you can use a spatula to carefully flatten the cookies if you want them to spread out more. This is a great trick if your cookies aren’t spreading as much as you’d like.

Step 7: Cool the Cookies

Once the cookies are done baking, let them cool on the baking sheet for about 5 minutes. This cooling time is crucial to allow the cookies to firm up slightly before transferring them to a wire cooling rack. If you skip this step, your cookies may break apart when you move them.

Step 8: Drizzle with Icing

While the cookies cool, prepare the icing by whisking together powdered sugar and milk or cream in a small bowl. The icing should be smooth and slightly runny—perfect for drizzling over the warm cookies. Once the cookies have cooled enough to handle, drizzle the icing generously over each one for a touch of sweetness that ties everything together.