1. Combine the milk, butter, sugar, salt and vanilla extract in a double boiler. Stir until butter melts and milk is steaming. Do not boil.
2. In a separate small bowl, dissolve yeast in warm water and set aside for 5 minutes.
3. In a large bowl, combine yeast, vanilla, egg and milk mixture. Add half the flour and mix until combined. Blend in remaining flour to make dough. It will have a sticky, stretchy consistency. Cover with a towel and let rise in warm place until double in size (30-40 minutes).
4. Meanwhile prepare filling by combining the butter, sugar, cinnamon, golden syrup and water in a heavy saucepan. Heat over low heat, stirring until well combined. A whisk will help incorporate these ingredients together.
5. Chop your pecans finely and add them to the pan, using a spoon to blend it together.
6. Spread dough evenly in a buttered 9x13 casserole dish. Pour the pecan mixture evenly over the top* and bake at 160 degrees Celsius for 25 minutes.
7. Let cool for 5 minutes before slicing into it.
*Alternatively, you could use a buttered bundt pan or springform pan, putting the pecans on the bottom instead of the top. If you choose this method, first line the buttered bottom of the pan with greaseproof paper before adding pecans. Dollop tablespoons of cake batter onto the pecans until evenly covered. After baking, invert the cake to cool, removing the paper from the top of the baked cake.