Place butter and marshmallows in a large microwave-safe bowl and heat in the microwave for 1 minute. Mix the marshmallows with the butter until creamy.

Add the rice cereal and mix well to coat evenly. Press into a pie dish. Use plastic wrap to press it down firmly.

In a saucepan, combine granulated sugar and cornstarch, then add water and lemon juice. Heat over medium heat.

Stir constantly from the bottom to prevent lumps. Once thickened and clear, remove from heat.

In a bowl, add egg yolks and about 1 cup of the mixture from step 4, mixing well. This step prevents the yolks from scrambling.

Return the mixture from step 5 to the saucepan and heat on low for about 30 seconds, then remove from heat immediately. Stir in butter.

Add grated lemon zest and mix well. Cover loosely with plastic wrap and let cool.

In a microwave-safe bowl, combine milk and marshmallows, and heat in the microwave for 1 minute to make marshmallow milk.

Add vanilla extract and let cool to room temperature (about 15 minutes).

Add yogurt and mix together. This creates the meringue-style yogurt cream.

Spread the lemon custard over the prepared rice krispie pie crust, then layer the meringue-style cream on top.

It's ready to serve!

Strained yogurt can be easily made using a coffee filter.