Preheat oven to 180C (350F). Grease a 22x33 cm (9x13 inches) pan and line with foil.
Crust
In a stand mixer or processor, cream butter, sugar and vanilla paste until light and fluffy. Add the flour and salt and mix until combined and crumbly.
Press firmly into the pan and bake for 20 minutes.
Topping
Melt the butter, sugar, maple syrup and cream in a heavy saucepan over a medium heat, when simmering add the nuts and combine over heat for 1 minute.
Remove crust from the oven, carefully pour over the caramel topping and spread evenly. Put back in oven and cook a further 15 minutes.
Cool in pan for 20-30 minutes before removing and slicing.