In a small bowl combine the yeast, warm milk, and sugar together until the yeast has been activated and appears foamy (approximately 5 minutes)
Using a kitchen aid bowl, hand whisk the flour, sugar, salt and vanilla to combine. Attach bowl to kitchen aid with the dough hook and add yeasted milk combination to combine.
Add eggs one at a time, mixing thoroughly for a total of 3 minutes. If the dough is still sticking to the side of the bowl and quite wet, you may need to add an extra tablespoon of flour.
Once the dough is not sticking to the side of the bowl anymore, it's time to add the softened butter in two separate parts. Add the first half of your butter and mix for five minutes. Scrape down the side of the bowl, then add the last half of the butter and mix for an additional 6 minutes. As before, if the dough is still sticking to the side of the bowl is sticking, you may need to add an extra tablespoon of flour.
Place the dough into a large clean bowl that is lightly coated in oil. Cover in plastic wrap and let is slowly rise for 1-2 hours. Then, degas the dough by lightly pressing with your hands and place in fridge overnight so that the flavor has plenty of time to develop.
Flour your counter and roll out the dough until it is about 9" by 15" and spread your jam and sprinkle pecans evenly over the dough. Roll up the rectangle so that the rolled log is 15 inches long and place in the freezer for 10 minutes. This will help to cleanly cut through the babka and allow for easy twisting.
Once chilled, cut log in half with a serrated knife so that you have two 15" pieces and the filling is exposed.
Fold the two separate logs on top of each other keeping the sides up as you do so, creating a long twist of tahini and hazelnut butter filled dough!
Place the twist in a greased loaf pan. Cover and place in a warm area for 1.5 hours until the dough has slightly rise and feels puffy.
Preheat your oven to 350 degrees.
Bake your babka for about 35-45 minutes until the top is a golden brown shade. If you happen to have a thermometer handy, check that the interior of the babka is 185-200 degrees in the thickest center part of the bread and remove from the oven.
Transfer to a cooling rack before serving and enjoy!