Preheat oven to 375°F (190°C).

Combine graham cracker crumbs and 3 tbsp white sugar in a medium bowl.

Mix in melted butter until well combined, then press evenly into a glass pie plate.

Bake the crust for 12 minutes, then remove and allow to cool completely.

Lower oven temperature to 325°F (163°C).

In a bowl, gently fold the egg yolks into the sweetened condensed milk until combined.

Add the key lime juice and lime zest to the condensed milk and yolk mixture and mix gently.

Pour the filling into the cooled pie crust and bake for approximately 17 minutes (until set).

Remove the pie and cool completely on a wire rack.

Place the stand mixer bowl and whisk attachment in the freezer to chill for at least 15 minutes before whipping cream.

When the pie is completely cooled, add 3 tbsp white sugar to the chilled bowl, pour in the whipping cream and whip at medium speed until stiff peaks form, about 3 minutes.

Spoon or pipe the whipped cream onto the top of the pie and garnish with fresh lime zest.

Place the pie in the freezer for 10 minutes before slicing. Serve immediately.