In a medium saucepan, combine egg yolks, granulated sugar, cornstarch, and whole milk. Cook over low heat, whisking continuously for 10 minutes until thickened.

Remove from heat and whisk in salted butter and vanilla extract. Cover with plastic wrap to prevent a skin from forming.

In a large bowl, sift matcha powder over the heavy whipping cream and whip on medium speed until soft peaks form.

Fold one-third of matcha cream into the cooled vanilla pudding gently. Mix until just combined.

Layer matcha pudding, vanilla wafers, and banana slices in serving dishes. Finish with matcha pudding on top.

Cover with plastic wrap and chill in the refrigerator for at least 4 hours or overnight.

Before serving, add a dollop of remaining matcha cream on each serving and garnish with banana slices and wafers.