In a small bowl activate the yeast by mixing it with 1/4 cup of warm water and 1 tsp of sugar. Stir to combine and set aside for 10 minutes or until yeast has become foamy and increased in size.
In a large bowl, stir together the spelt flour, sugar, salt and anise seeds. Once the yeast has activated, make a large well in the middle of the dry ingredients and pour the yeast mixture into it. Slowly drizzle the vanilla extract and the melted and cooled butter on the dry ingredients around the edge of the bowl. Using your hand, slowly move around the bowl and mix a little of the ingredients around the yeast into it until the yeast is just incorporated. Add the egg to the bowl and about half the warmed milk. Continue to mix with your hands adding the rest of the warmed milk until you have a shaggy looking dough.
Turn the dough out onto a lightly floured surface and knead gently until smooth. Form into a ball, place back in the mixing bowl, cover with a clean tea towel and place somewhere away from drafts to proof until doubled. This will take approximately 1.5 hours at room temperature (21C, 70F). Line or grease a large baking sheet and set aside.
In a medium bowl, mix and rub all the streusel ingredients together with your fingers until it resembles course crumbs. Place in the fridge to chill.
Once the dough has doubled in size, place it on a lightly floured surface and press it down with your hands into a rectangular shape. Dust the top of the dough with flour, then roll it out to the size of your baking sheet. Dust the top with flour again, fold the dough into quarters, place it on your baking sheet and unfold it, pressing the dough to the edges and corners if need be (or folding the edges over because you rolled it too big like I did!).
Poke the dough all over with a fork, then spoon the tart jam or jelly onto the dough and spread evenly right to the edges with a spatula. Remove the streusel from the fridge and distribute it evenly over the jam. Gently press down on the streusel to help it adhere to the jam. Put the assembled streuselkuchen back in a place without drafts and allow to proof again until it has risen in volume by 50%. This will take approximately 40 minutes at room temperature (21C, 70F). Preheat the oven to 325 degrees F.
Once the dough has risen, bake for 30 minutes or until the edges are a dark golden brown. Remove and allow to cool on the baking sheet for 30 minutes before transferring to a cooling rack. Cut the cake into wide strips (easier for dunking in coffee) or any shape you like before serving.