Line several baking sheets with parchment paper. Set aside.
In a large bowl, whisk together the cake flour, flour, sugar, baking powder, cinnamon and sea salt. Cut the cold butter pieces into the flour mixture using a pastry cutter, two forks or your hands. I like to mix until I see small pieces, about the size of peas
Mix the egg and 2/3 to 3/4 cup (160 g to 180 g) of cream together (see note about cream below) in a small bowl and then drizzle over the flour mixture. Using a fork, stirring until it just starts to form into a dough.
Strain the strawberries, pressing out any excess moisture and reserving the liquid for the glaze (it's very important to get as much moisture out of the berries as possible, without smashing them). Add the berries to the scone dough.
I like to use a fold and press technique when adding the strawberries. Fold half of the dough onto itself and press down so that the berries are in the middle. Grab any rogue strawberries, set them on top of the dough heap and repeat the process until it looks just mixed. The addition of fresh fruit will make the dough a bit slick and snotty…don’t panic. It’s perfect.
Use a 1/2 cup muffin/cupcake scoop or 1/2 cup measuring cup to portion out eight mounds of dough on the prepared baking sheet leaving 3-inches (8-cm) between scones. Gently press down the tops to level a bit and press in any jagged areas on the sides of the scones. You want the dough cohesive, but not packed. Set in the freezer (or fridge) for 30 minutes and preheat the oven to 400℉ (204℃). Add the egg wash, if using (see note below), and sprinkle with Demerara sugar. Bake in the center of the oven for 19 minutes. When done they will be lightly bronzed around the edges and golden over the tops. Make sure the areas around the strawberries are baked through. Let them cool on the sheet, in a draft-free area, for about 15 minutes before removing to a rack to finish cooling. Let cool to room temperature before adding the glaze (if using).