Place 2 cups crushed pretzels in the bottom of a 13 x 9 x 2-inch baking dish. Pour 1 cup melted salted butter carefully over the crushed pretzels.
Bake for 10 minutes and remove immediately. Do not overbake or it won't cut with the other layers. Cool the crust before adding the next layer.
In a large bowl, cream together 1 (8-ounce) package cream cheese,1 cup granulated sugar, and 2 teaspoons vanilla extract using an electric hand mixer.
Fold in 1 (8-ounce) container Cool Whip then spread the cream cheese mixture evenly over the cooled crust.
Drain 2 (20-ounce) cans crushed pineapple then pour it into a medium-sized bowl. Add 1 (3.4-ounce) instant lemon pudding mix and stir to combine. Spread the pineapple mixture over the whipped topping layer.