Preheat oven to 180 degrees. Line 2 x 23cm cake tins with baking paper.
Place a small saucepan over high heat and add butter, maple syrup, pears and coffee and bring to the boil. Once bubbling, reduce heat to low and let simmer for 6-10 minutes to allow pears to soften. Set aside.
Blend pecans in a blender or food processor until fine. Keep half the pecans for the cake mixture, setting aside the other half for the filling.
Sift together flour and baking powder in a large bowl.
In another large bowl, beat butter and sugar until fluffy. Adding in eggs one at a time and beating until well combined. Add coffee and fold in flour and half the grind pecans.
Divide cake batter between the two cake tins and place pears on top of each cake. Keep the caramel sauce from the pears for the filling. Place in the oven and bake for 35-40 minutes.
Remove from oven to allow to cool before icing.
In a small bowl, mix mascarpone, the remaining caramel from the pears and half the reserved pecans with a whisk. Bit by bit, add in the icing sugar to create a runny glaze.
Once you've allowed cakes to completely cool, assemble the cake by covering one with the filling mixture. Place the other cake on top and lightly press down. Scatter the top cake in reserved pecans and pour over glaze.