Preheat and prep: Heat oven to 350°F (175°C). Grease and flour a 9'x13' dish or line with parchment.

Mix dry cake ingredients: Whisk together flour, baking powder, and salt in a bowl.

Cream butter and sugar: In a large bowl or stand mixer, beat butter with granulated sugar until light, about 2–3 minutes.

Add eggs and vanilla: Beat in eggs one at a time, then stir in vanilla.

Combine wet and dry: Add the dry ingredients and milk alternately, mixing gently until just combined.

Bake: Pour batter into prepared pan and bake for 30–35 minutes or until a toothpick comes out with a few crumbs. Cool completely on a rack.

In a medium saucepan, whisk sugar and cornstarch, then gradually whisk in milk. Cook over medium heat until thickened, about 5–8 minutes.

Temper the yolks: Beat egg yolks, and slowly add hot milk to yolks while whisking. Whisk yolk mixture back into saucepan and cook for 2–3 more minutes.

Remove from heat and stir in vanilla. Let cool briefly before folding in bananas and wafers.

Macerate strawberries: Toss sliced strawberries with sugar in a bowl and let sit for 10–15 minutes.

Make whipped cream: Beat cold heavy cream with powdered sugar and vanilla until soft peaks form.

Spread the banana pudding layer evenly over the cooled cake, then top with macerated strawberries and spread whipped cream across the top.

Refrigerate for at least 1 hour before serving to set.