Gently heat 180 ml (3/4 cup) milk in a small saucepan until hot, but not boiling.
200 ml non-dairy milk
Pour the hot milk into a heat-safe mixing bowl. Add 3 tablespoons maple syrup and 45 grams (3 tablespoons) coconut oil, whisking until the oil has melted.
3 tablespoons maple syrup, 45 grams coconut oil
Check the temperature with your finger. It should be warm, but not hot, to the touch.
Whisk in 2 1/4 teaspoons yeast. Set aside for 15 minutes for the yeast to bloom.
2 1/4 teaspoons dry yeast
After 15 minutes, the yeast should be bubbly and have expanded significantly. If it hasn't, you need new yeast.
Add 150 grams (1 cup) of the flour, 1 teaspoon cinnamon, and 1/4 teaspoon salt to the bowl and stir with a wooden spoon or spatula to combine.
400 - 450 grams light spelt flour, 1 teaspoon cinnamon, 1/4 teaspoons sea salt
Add another 250 grams (1 2/3 cups) of flour to the bowl and stir. Once the dough becomes too difficult to stir, tip it out onto a lightly floured work surface.
400 - 450 grams light spelt flour
Knead, adding up to 50 grams (1/3 cup) additional flour as required, for 6-8 minutes, until a soft, smooth dough forms. Don't over-mix.
400 - 450 grams light spelt flour
Place the kneaded dough back into the bowl. Cover and set aside in a warm, draft-free place to rise for about an hour, or until doubled in size.
Once the dough has risen, preheat the oven to 180°C (350°F) and line a large baking sheet with parchment paper.
Roll the dough out on a lightly floured surface to fit your baking sheet (about 40x30cm (~12x16in.)) or make two smaller cakes if needed. Place the rolled out dough onto your prepared baking sheet.
Prepare the plums. Wash and de-stone, cutting the plums into attached quarters as pictured. Spread the plums evenly over the cake base.
500 grams prune plums (zwetschgen)
Make the streusel. Mix 150 grams (1 cup) spelt flour and 100 grams (1/2 cup) coconut sugar in a bowl. Add 60 grams (1/4 cup) coconut oil and 1 tablespoon milk, and use your hands to mix into a crumbly steusel. Sprinkle evenly over the plums.