Preheat oven to 160°C. Line a baking tray (or two) with paper
Place butter and treacle into Thermomix bowl and melt 4 min/60°C/speed 1.
Add bicarb soda and mix 3 sec/speed 4.
Add all remaining crust ingredients and mix 10 sec/Reverse/speed 4.
Press into a shallow tart tin with removable base. We used a 20cm square flan tin. Any remaining mixture can be made into cookies. You don't want to overfill the tart tin or you will have no room for your filling.
Bake 15 minutes until golden and fragrant. Cool completely before pressing the centre down with a spoon if it has risen. It will push easily.
To make the ganache, place all ingredients into the Thermomix bowl and melt 5 min/60°C/speed 1. Stop and scrape down sides of bowl about 2 minutes in to make sure the chocolate is all below the level of the blades.
Spread into the tart shell and top with toasted pecans. Chill before serving.