In a medium saucepan, whisk together granulated sugar, cornstarch, and fine sea salt. Gradually pour in the whole milk while whisking constantly until well combined. Cook over medium heat, stirring frequently, until the mixture starts to simmer and thickens (about 5-8 minutes). Remove from heat once bubbling, then set aside to cool slightly.

In a separate bowl, whisk the large egg yolks together. Slowly drizzle the warm milk mixture into the yolks, whisking continuously to temper the eggs. Return the tempered mixture to the saucepan and cook over low heat, stirring frequently, until the custard thickens further (about 3-5 minutes). Remove from heat and stir in the unsalted butter and pure vanilla extract until smooth, then refrigerate until chilled.

While the custard chills, wash and slice the fresh strawberries, then combine them in a bowl with a sprinkle of sugar. Allow the strawberries to sit for about 10-15 minutes to release their juices. Just before layering, slice the firm-ripe bananas to ensure they stay fresh and prevent browning.

In a greased 9x13-inch baking dish, begin layering your ingredients. Place a layer of vanilla wafers at the bottom, followed by half of the chilled custard, a layer of banana slices, and a layer of the sugared strawberries. Repeat the layering process with the remaining wafers, custard, bananas, and strawberries for a beautiful, multi-layered effect.

In a small bowl, combine the unsalted butter, light brown sugar, granulated sugar, all-purpose flour, ground cinnamon, freshly grated nutmeg, and ground cloves. Mix until crumbly. If desired, add chopped toasted pecans or walnuts for extra crunch. Sprinkle this mixture generously over the top layer of the pudding.

Preheat your oven to 350°F (175°C). Place the assembled baking dish in the preheated oven and bake for 30-35 minutes, or until the topping is golden brown and crisp. Keep an eye on it to avoid burning, and let your Strawberry Crunch Banana Pudding fill your kitchen with its delicious aroma.

After baking, allow the dessert to cool for about 45 minutes at room temperature. For an even firmer texture and improved flavors, refrigerate the pudding overnight. Slice and serve chilled, enjoying the delightful contrast of creamy custard, fresh fruit, and crunchy topping with every bite.