In a small bowl, stir together yeast, warm water, and a pinch of sugar. Allow to sit for 5 minutes until it’s lightly foaming and bubbly.
In a large mixing bowl, whisk together 2 cups flour, sugar, and salt. Set aside.
Whisk together eggs and set aside.
In a small saucepan, melt together milk and butter until butter has just melted. Remove from the heat and add vanilla extract. Let mixture stand for about 5 minutes to cool, or until the mixture is warm to the touch.
Pour the milk mixture into the dry ingredients. Add the yeast mixture too and mix with a spatula. Add the eggs and place the bowl in your stand mixer fitted with a dough hook. As the mixture beats on low speed, add an additional cup of flour.
Beat the mixture until the eggs are incorporated into the batter. Keep mixing. The dough will stick to the sides of the bowl. Stop the mixer and scrape down the sides of the bowl and add up to 1/2 cup more flour and beat in. The dough will be lightly tacky and slightly sticky after 5 minutes of kneading.
You can make this dough without the use of a mixer, using a firm spatula or wooden spoon to bring the dough together. Add the remaining 1/2 cups flour as necessary to create a firm, tacky and lightly sticky dough. Knead on the counter top to really get it together.
Place the dough in a large, greased bowl. Cover with plastic wrap and a kitchen towel. Place in a warm space and allow to rest until doubled in size, about 1 hour though the time will be longer if your kitchen is cool.
While the dough rests, make the chocolate filling.
In a heatproof bowl over a double boiler, melt together the chocolate and butter. Stir until smooth and glossy. Remove from the heat and stir in the salt, cinnamon and honey.
Let the chocolate cool to room temperature. This step is very important! We’ll need the chocolate at room temperature before we add the cookie crumbs so the finished mixture is spreadable. Give the chocolate about 30 minutes to come to room temperature.
Stir in the chocolate cookies which should make the chocolate mixture thick but still spreadable.
Make the cinnamon crumble topping now. In a medium bowl toss together flour, brown sugar, cinnamon and salt. Add the cold butter and use your fingers to work the butter into the dry ingredients, creating a crumbly mixture. Set aside.
To assemble the muffins, start by rolling out the dough.
Once the dough has nearly doubled in size, knead it gently on a well floured work surface. I actually roll out my dough on my counter. Use a floured rolling pin to roll the dough into a roughly 18×12-inch rectangle, keeping the 18-inch side closest to you.
Spread generously with filling. You’ll have enough filling for two babka recipes, so divide the filling in two and save the rest in a freezer safe bag for future use.
Now we’ll roll up the dough. Starting from the 18-inch side, we’re going to fold the upwards in fourth. Instead of rolling like a cinnamon roll, we’re making four big, flat folds.
You’ll end with a roughly 18-inch long flat log.
Use a large sharp knife to divide the dough in half vertically. And slice each half into 12 even pieces. You’ll have 24 small vertical slices of dough total with your 18 inch log. This will most likely be messy. That’s ok. It will still bake beautifully.
Lightly grease and flour a standard muffin tin.
Layer two pieces of babka dough into each muffin cup, pinching the dough to squeeze out some of the filling and layering the pieces atop one another. Repeat until all the muffin cups are filled. Again, it doesn’t matter if it’s messy. It will turn out just fine after baking.
Sprinkle each muffin cup with half of the crumble topping. Save the remaining crumble topping in a freezer safe bag for your future self.
At this point, you can cover the pan in plastic wrap and place the pan in the refrigerator to bake tomorrow morning. When you’re ready to bake, place the pan on the counter to come to room temperature while the oven preheats.
Place a rack in the upper third of the oven and preheat oven to 375 degrees F. Allow the muffins to rest and rise just slightly while the oven preheats, approximately 20 minutes.
Bake for 16 to 18 minutes until the muffins have risen, are golden and bubbling. Remove from the oven and allow to cool for at least 15 minutes before using a knife to gently remove them from the pan for serving. That’s the hardest part, waiting 15 minutes to eat!