Instructions

1. First, make the graham cracker butter. In a small bowl, combine the graham cracker crumbs, melted butter, agave, milk, vanilla, and salt. Use a silicone spatula to stir together until it forms a paste. It will be slightly thin, so set aside to thicken for 5-10 minutes while you make the rest of the ice cream.
2. Next, make the ice cream. In a medium bowl, add the sweetened condensed milk, lemon zest, vanilla extract, lemon extract, and salt. Stir to combine and set aside.
3. In a stand mixer fitted with the whisk attachment, beat the heavy cream on low speed, gradually increasing to high, until soft peaks form and the whipped cream just begins to hold its shape, about 1 minute. If desired, add a few drops of yellow food coloring to turn the ice cream pale yellow.
4. Pour in the sweetened condensed milk mixture and mix on low speed until just combined and no streaks of sweetened condensed milk remain. 
5. Get out two quart containers (any freezer safe container works, though, like a 1-pound loaf pan or 9-inch round pan). Spoon the ice cream mixture into each quart container to fill it up about 1/3 of the way. Drop small spoonfuls of the graham cracker butter, lemon curd, and marshmallow fluff on top. Repeat the process, layering with more ice cream, graham cracker butter, lemon curd and marshmallows, until you reach the top of the container.
6. Use a butter knife to gently swirl everything together, then cover with a lid or plastic wrap and place in the freezer to set for at least 8 hours before serving. When tightly covered, ice cream will keep in the freezer for up to 2 months.