Adjust the oven rack to the middle position and pre-heat the oven to 350ºF (180ºC). Lightly butter two 6 inch (15cm) round cake tins and line their bottoms with rounds of baking/greaseproof paper.
In a large bowl (or the bowl of a stand mixer if using it), sift together the gluten free flour blend, almond flour, sugar, baking powder, xanthan gum and salt.
Add the softened butter and, using your fingertips, work it into the dry ingredients until you get a mixture resembling breadcrumbs. You can also use a stand mixer fitted with the paddle attachment or a hand mixer fitted with the double beaters.
In a separate bowl, mix together the egg, milk and vanilla bean paste, and add them to the flour-butter mixture in two batches, whisking well after each addition, until you get a smooth cake batter with no flour clumps. (Again, you can do this by hand using a balloon whisk, or using a stand mixer fitted with the paddle attachment or a hand mixer fitted with the double beaters.)
Evenly divide the cake batter between the two lined cake tins and smooth out the top.
Bake at 350ºF (180ºC) for about 22-24 minutes or until well risen, golden brown on top and an inserted toothpick comes out clean.
Allow to cool in the cake tins for about 10 minutes before turning them out onto a wire cooling rack to cool completely.
For macerated strawberries & strawberry syrup:
In a large bowl, combine the halved and quartered strawberries, sugar, lemon juice and vanilla. Mix well until the strawberries are evenly coated with the sugar.
Cover and allow to sit either at room temperature for 1-2 hours or in the fridge overnight, stirring occasionally.
Once the strawberries have released their juices, pass them through a sieve to drain the juices, then return the strawberries back into the bowl and set aside until needed.
Pour the juices into a saucepan and cook over medium-high heat with frequent stirring until thickened and syrupy, but not quite jam-like. This should take about 5 minutes. Once thickened, set aside to cool.
For stabilised whipped cream:
In a large bowl, combine the cold double/heavy cream with powdered/icing sugar and the vanilla. Whisk them together until very soft peaks form. You can do this by hand using a large balloon whisk, or using a stand mixer fitted with the whisk attachment or a hand mixer fitted with the double beaters. If using a stand/hand mixer, whisk on the low/medium-low speed setting – this will ensure that you don't over-whip the cream.
In a separate bowl, whisk the cold cream cheese until it loosens up slightly and is completely smooth.
Add the cream cheese to the loosely whipped cream. Whisk until combined and soft peaks form.
Assembling the cake:
If necessary, level off the sponges with a sharp serrated knife.
Place the bottom sponge on a cake stand or serving plate of choice.
Spread half of the whipped cream on top and use a small offset spatula to spread it out into an even layer.
Arrange half of the strawberries on top of the cream in an even layer.
Place the other sponge on top, with the bottom of the sponge facing upwards (this will give you a nice flat top).
Spread the other half of the whipped cream on top of the sponge.
Arrange the remaining strawberries on top of the cream.
Finally, just before serving, drizzle the top of the cake with the strawberry syrup. You can also drizzle the individual cake slices with leftover syrup.