Make the babàs: Prepare 18 (3-4 ounce) babà molds, ceramic ramekins, brioche molds, or muffin tins by spraying with nonstick baker’s coating or rubbing them with softened butter and dusting them with flour, shaking off the excess.

In a medium bowl, whisk together the dry ingredients: bread flour, all-purpose flour, sugar, and salt. In the bowl of a standing electric mixer, combine the yeast, milk, and 1 cup of the flour mixture, and allow to proof for about 10 minutes or until bubbly.

Using the paddle attachment, beat in three-quarters of the remaining flour mixture. Next, beat in the eggs, one at a time, beating until they are completely incorporated. Add the butter and beat until it has been incorporated, and no butter bits remain, about 5 minutes. Finally, beat in the remaining flour, continuing to beat until the dough is smooth and elastic, though still soft and sticky, about 5 minutes. 

Transfer the dough to a lightly oiled bowl and cover with plastic wrap. Allow the dough to rise at room temperature until it doubles in size, about 1 hour. (If the dough gets too warm, the butter will begin to melt out of it.)

Punch down the dough and scoop or spoon evenly sized portions into the molds, filling about half-way. Smooth the tops with your fingers dipped in cold water. Rise at warm room temperature until the dough has almost doubled in bulk again, 1 to 2 hours.

Preheat the oven to 350°F. Bake the babàs 15 to 20 minutes or until they are nicely browned and have begun to pull away from the sides of the molds. Remove from the oven and cool to room temperature in the molds placed on a wire rack.

Make the syrup: In a small pot, bring the water and sugar to the boil over medium heat. Continue to boil for 1 to 2 minutes or until the syrup is completely clear. Remove from the heat and stir in the Limoncello and the lemon juice. 

Remove the babàs from the molds and arrange them in a single layer on baking pans or other shallow container with a lip. Prick each babà with a sharp skewer in several places. Pour the syrup slowly over top, making sure all the babàs are coated. Cover and leave the babàs to soak for 1 to 2 days at room temperature, turning them once or twice so that they are impregnated with the syrup.

When ready to serve, drain the babàs, split open with a serrated knife and spoon or pipe about 2 tablespoons of lemon cream filling into each babà.