Preheat the oven to 350°F. Place a metal mixing bowl in the freezer for at least 20 minutes before making the ice cream to ensure the cream whips up properly.
Combine flour, sugars, baking powder, vanilla, and butter. Mix until a crumbly texture forms. place on a parchment lined baking sheet and bake for 15-20 minutes.
for the ice cream
In a bowl, add lemon juice, lemon zest, sweetened condensed milk and vanilla.
In a chilled metal bowl, carefully pour heavy cream and whip until stiff peaks, about 5-10 minutes. Fold in lemon sweetened condensed mixture and poppy seeds.
Layer the ice cream mixture into a freezer-safe container, followed by a layer of cookie crumble. Add another layer of ice cream, then finish with a few more pieces of crumble on top. Cover with a piece of parchment paper and freeze for at least 6 hours, or overnight, before serving.