Preheat the oven to 350 degrees. Crush the pretzels. In a large bowl mix in the pretzels, melted butter and sugar well. Firmly press the mixture into the bottom of a round 8 in spring form pan. Bake for 10 minutes and set aside to cool.
Whisk well 1 package of Jello mix with a 1/4 cup boiling water and 1 cup of yogurt in a microwaveable bowl. Microwave on HIGH for 2 minutes, stirring after each minute. Pour over the crust into prepared pan. Refrigerate 40 to 45 min or until set but not firm.
Repeat in same pan with another package of Jello mix to make a 2nd layer.
For the 3rd layer we want a glossy shell. Mix half the package with 1/2 cup cup boiling water and proceed the same way, reducing microwave time. Sprinkle the sliced almonds and pour on top.