1-First Step: Gather and measure all ingredients. Line a 9-inch pie pan so the crust presses in evenly. If using regular-sized marshmallows, count out about 24 to equal 3 cups of mini marshmallows. Chill the heavy cream so it whips more reliably.

2-Second Step: Combine 3 cups mini marshmallows and 1/2 cup whole milk in a small saucepan. Melt over low heat, stirring constantly until the marshmallows are completely smooth and uniform with the milk. Remove from heat and let cool for 30 minutes. Cooling prevents the hot mash from deflating the whipped cream later.

3-Third Step: While the marshmallow mixture cools, pour 1 1/2 cups heavy cream into a chilled mixing bowl and whip to soft peaks. Soft peaks should hold shape briefly but still gently fold over when you lift the beater.

4-Fourth Step: Gently fold the cooled marshmallow mixture into the whipped cream using a rubber spatula. Fold in thirds to keep the mixture airy: add one third, fold until almost incorporated, repeat, then add the final third and fold until uniform. Avoid overmixing to keep the filling light.

5-Fifth Step: In a medium bowl, mix 1 1/2 cups graham cracker crumbs with 1/2 cup melted butter until crumbs are fully coated. Press the crumb mixture firmly into the bottom and up the sides of a 9-inch pie pan to form an even crust. Press with the back of a measuring cup for an even surface. A firm press helps the crust hold together when slicing.

6-Sixth Step: Spread the marshmallow and cream filling evenly into the graham cracker crust using a spatula. Smooth the top for a neat finish. Melt 1/2 cup creamy peanut butter gently (low heat or microwave in short bursts and stir) and either drizzle or spread over the top of the pie. For a glossy finish, apply with a warm offset spatula. For swirls, drizzle and use a toothpick to make designs.

7-Final Step: Chill the assembled pie in the refrigerator for at least 2 hours or overnight until set. This helps the filling firm and the crust set. Slice into 8-10 pieces. Serve chilled with optional whipped cream, crushed peanuts, or a dusting of cocoa powder.