In a large saucepan, combine the chopped fresh strawberries, granulated sugar, and lemon juice, tossing until evenly mixed. Place the saucepan over medium heat and allow the mixture to bubble gently for 2 to 3 minutes.

Make a slurry by mixing the all-purpose flour with 1 tablespoon of water. Stir this into the strawberry mixture and continue cooking for another 1 to 2 minutes until thickened. Remove from heat and allow to cool.

In a small bowl, mix the all-purpose flour, granulated sugar, melted vegan butter, and ground cinnamon until crumbly. Place the crumb topping in the fridge.

Preheat your oven to 180°C (355°F) and line an 8-inch square baking pan with parchment paper. In a large bowl, whisk together the dry ingredients: flour, sugar, baking powder, and salt.

Add the wet ingredients—dairy-free yogurt, dairy-free milk, oil, optional vinegar, and vanilla extract—and whisk until combined.

Pour the cake batter into the prepared pan, smooth the top, spoon the cooled strawberry layer over, and sprinkle the crumb topping on top. Bake for 1 hour to 1 hour and 5 minutes.

Cool the cake in the pan for 30 minutes. Carefully lift out using the parchment and transfer to a wire rack to cool completely before slicing into 16 portions.