Preheat oven to 180 C / Gas 4. Grease and lightly flour a springform tart tin and set aside.
For the base:
In a food processor, combine the flour, baking powder, bicarb and lemon zest, and pulse several times. Add cubed butter and pulse until mixture resembles breadcrumbs. Add egg and egg yolk and mix well until a soft dough ball is formed and easily separates from the bowl. Add 1 extra teaspoon of water or milk if needed. Wrap tightly in cling film and chill in the fridge for 20 minutes.
Remove the dough from the fridge and roll out over a lightly floured work surface to a thickness of 5mm. Transfer to the springform tin and gently press into base and sides. Trim any overhang and discard.
Bake in the preheated oven for 15 to 20 minutes, or until slightly golden. Remove from the oven and let cool down completely. Release the springform and place onto a serving dish.
For the filling:
Spread the dulce de leche over the base. In a bowl, whisk the cream and caster sugar until stiff peaks are formed. Spread evenly over dulce de leche layer. Arrange the sliced strawberries over the top in concentric circles until the top is covered. Slice and serve.