<p>Mix together the crushed speculoos and the melted butter. Spread the resulting mixture at the bottom of a springform pan and place in the oven.&nbsp;</p><p><br></p><p>Mix the cream cheese, eggs, sugar, sour cream, vanilla extract, and lemon zest.&nbsp;</p><p>Gently pour the mixture over the crust and place in the oven.&nbsp;</p><p>Let cool for 1 hour, then pour the warm speculoos mixture over the cheesecake.</p><p>Place the cheesecake in the refrigerator for at least 12 hours.</p>