20 OREO Cookies, finely crushed, divided
1/4 cup (60 mL/60 g) butter, melted
1/2 cup (125 mL/100 g) sugar
1/3 cup (75 mL/40 g) cornstarch
3 cups (750 mL) half-and-half
2 egg yolks
2 Tbsp. (30 mL/30 g) butter, cut into small pieces
1 tsp. (5 mL) vanilla
3 bananas
1 cup (250 mL) thawed frozen whipped topping