1 ½ cups crushed speculoos cookies (or any butter cookies)
½ cup melted butter
2 Tbsp brown sugar
180 oz or 1 1/2 cups cream cheese
1 ¼ cups sugar
1 vanilla bean, seeds scraped
½ tsp salt
zest of 2 lemons
6 egg yolks
½ cup heavy cream
½ cup plain yogurt or sour cream
Preheat the oven to 170°C (350°F).
Prepare the Crust. In a bowl, combine the crushed cookies, melted butter, and sugar until well-mixed. Press the cookie crust to the bottom and sides of a 6- or 8-inch springform pan to create an even layer. The bottom and sides of the crust should be around 1/4-inch thick.
Bake in the oven using the bottom heat function for 10 minutes. Let the crust cool completely in the pan before pouring in the custard.
Prepare the Custard. In a bowl, cream together the cream cheese, sugar, scraped vanilla seeds, salt, and lemon zest until smooth. Add the yolks in pairs, scraping after each addition. Add the heavy cream and yogurt or sour cream, and mix at low speed until completely smooth.
Spread the custard over the crust and bake in the oven until the custard is fully set.
Allow the cake to cool gently, then remove from the pan and cool completely before serving.