In a medium-size saucepan combine the milk, cream, sugar and salt. Bring to a simmer over medium heat, just until the milk starts bubbling around the edge of the pot. Temper the eggs and add to the saucepan with the cream mixture. Bring the mixture to a boil and whisk until it thickens. Remove from heat and stir in the butter and vanilla.
In a mixing bowl, combine the heavy cream, sugar and vanilla extract. Beat on medium high speed with a hand or stand mixer until soft peaks form. Mix in a portion of this with the pudding, it gives it a light and airy texture. The rest is for the topping.
Working in either a 1.5-2 qt baking dish or smaller jars or cups layer vanilla wafers, sliced bananas and pudding. Top with the homemade whipped cream.