Preheat oven to 175° C. Combine cookie crumbs in a large bowl with sugar and butter and stir until moist. Press crumb mixture evenly onto the bottom of a 9-inch springform pan. Bake 15 to 20 minutes or until golden brown and set. Cool completely.

Combine orange juice and brown sugar in a small saucepan. Bring to a boil and stir until sugar dissolves. Simmer for 10 to 15 minutes or until mixture is reduced. Set aside to cool.

In a stand mixer fitted with a paddle attachment, beat cream cheese and sugar until smooth. Add orange zest, sour cream, flour, and salt and beat 2 minutes. Add eggs 1 at a time mixing well in between each addition. Mix in cooled orange juice mixture and beat to combine. Pour the cream cheese mixture on top of the crust and place the springform pan in a large roasting pan. Pour warm water into roasting pan to come halfway up the sides of the springform pan. Bake 1 ½ hours or until just set in the centre. Cool 1 hour on a wire rack and then at least 4 hours in the refrigerator or overnight.

Thinly slice oranges and place in a medium saucepan. Add sugar and water and bring to a boil over medium-high heat. Reduce to a simmer and cook 20 to 30 minutes or until oranges are translucent and tender. Let cool slightly. Remove orange slices with a fork and gently place all over top of cooled cheesecake. Drizzle ¼ cup of the remaining syrup over the cake and cut into 8 slices to serve.