Place all ingredients in a food processor and blitz until blended. Alternatively zap the butter and cream cheese in the microwave until just soft but not melted. Roughly chop up further with a knife. Add remaining tart base ingredients to the butter mixture and stir until just combined. Shape into a ball and refrigerate covered until dough firms up.
Line a 20-25 cm pie dish with the dough. Either roll out the dough with a rolling pin between 2 sheets of baking paper or use your fingers to press the dough into the sides and base of the dish. If the dough tears use your fingers to patch it. Create a nice line along the edges by using your fingers to shape it. Trim with a knife if need be. If dough is too soft to use, refrigerate till it firms.
Use a fork to prick the base all over. Bake at 165C/ 330 F fan forced for 10 minutes. Then bake covered with aluminium foil for another 10 minutes to prevent browning. Allow to cool while you prepare the filling.
To make the filling
Beat the eggs in a large mixing bowl. Add the sweetener and keep whisking until blended.
Whisk in the cream and the lemon rind and allow to sit for a few moments.
Pour the filling into the pastry base. If adding berries, place them onto the pie base first and pour the egg filling over them
Bake at 165 C / 330 F fan forced for 25-35 minutes or the filling has set around the edges. The centre can still be slightly jiggly as it will firm up once the lemon tart cools.
Allow to cool in the fridge for a couple of hours prior to serving.
To serve, dust with a little powdered erythritol or xylitol or confectioners sweetener with a small sieve. Serve topped simply with a dollop of fresh whipped cream. A scattering of fresh berries also taste great served on top, especially if it is a plain lemon tart.
Notes
Add 1/2 cup of fresh or frozen blueberries or raspberries for a Lemon Berry Tart. Place them on the par cooked base before you pour the egg mixture into the tart.Taste the filling mixture before you pour it into the base and adjust the sweetness of the filling to suit your taste if required. If you use a wider dish to bake in, the filling will not take as long to cook. If it is set on the edges and ever so slightly jiggly in the middle, remove it from the oven.Use blanched almond flour if you want a pastry more like a traditional short crust pastry. The recipe works fine with almond meal as well but it will look a bit more like a whole meal pastry. You will find if you use almond meal that it absorbs more moisture so the base will be slightly drier. If too dry you can add additional butter. Do it sparingly though if needed.If you make the pastry thinner, any left over pastry can be refrigerated for up to 3 days or frozen for use at a later date.