In a large mixing bowl, combine brioche flour, sugar, and salt. Gently warm milk until lukewarm, then whisk in yeast and let it foam for about 5 minutes. Add eggs and melted butter to the flour mixture, and gradually stir in the yeast mixture. Knead the dough for about 10 minutes until smooth and elastic, then cover and let rise in a warm place for 1-2 hours, or until it doubles in size.

While your dough is rising, prepare the filling. In a medium bowl, mix brown sugar, cinnamon, and optional chopped nuts. Once the dough has risen, roll it into a large rectangle about 1/4 inch thick. Spread softened butter over the dough, then sprinkle the brown sugar mixture on top.

Starting from one long edge, roll the dough tightly to form a log. Slice the log into 1-inch sections and place the first slice in the center of a greased baking dish, coiling the remaining slices around it.

Cover the formed cake and let it rise again. Refrigerate overnight or allow it to rise in a warm area for 30-40 minutes until doubled in size.

Preheat your oven to 350°F (175°C). Bake the Giant Cinnamon Roll Cake for 25-30 minutes, or until golden brown and a toothpick comes out clean.

Remove from the oven and allow to cool for 10-15 minutes. Prepare the glaze by whisking together confectioners' sugar, milk, and vanilla extract until smooth. Drizzle over the warm cake.