Combine the flours, sugar and salt in a medium bowl. Add the butter cubes and rub them into the dry ingredients with your fingertips until the mixture has the texture of damp sand with some pea-sized lumps of butter remaining.
Stir the apple cider vinegar into 5 tbsp of ice water. Drizzle 3 tbsp of the water over the dry ingredients in the bowl and gently stir together with your hands until the dough starts to come together. Squeeze a bit of the mixture in your fist - if it comes together it's perfect. If it seems to dry to stick together, drizzle in a bit more water, mix and test again. Form into a rough ball.
Tip the contents of the bowl out onto a piece of clingfilm and bring any crumbs into the ball of dough. Pat down into a disk, wrap in the clingfilm and chill for at least 2 hours or preferably overnight.
When ready to bake, preheat the oven to 200 C (400F). Cut a piece of baking paper to fit the size of your baking tray. Place the baking paper onto a work surface and roll the dough out on it into a rough oval or rectangle (just under 2mm/ 1/4-inch thick). Transfer the baking paper and dough onto the baking tray. Dock all over with a fork and brush with beaten egg.
Bake for 20-25 minutes until dark golden all over. Check on the pastry halfway through the baking time - if there are any air bubbles flatten them with a spatula. Let the pastry cool completely.
Meanwhile slice the strawberries (I cut mine into 3 or 4 slices each) and toss with 1 tbsp of sugar in a bowl. Set aside.
In another bowl mix the ricotta & yogurt (or mascarpone), sugar and vanilla extract.
Once the crust is cooled, frost it with the ricotta mixture then dot with the jam and decorate with the strawberry slices (arranged overlapping in lines). Slice the tart and serve immediately.