Heat 120 ml (1/2 cup) stock until simmering, then sprinkle over 2.5 tablespoons of flour, continuously whisking until a smooth roux, or paste, forms. Remove from heat.
Sprinkle the sugar over the warm milk, and stir in the fresh yeast. Let it sit for about 10 minutes, until foamy.
When the yeast mixture is foamy, add the roux, glace, additional milk, egg, and melted butter, and stir until combined.
Add the flour about a cup at a time, stirring after each addition.
With the last addition of flour, tip contents onto a clean surface, and knead the remainder of the flour in with your hands, until the dough forms a smooth ball.
Place the dough in a lightly oiled bowl, cover with a damp cloth, and let rise about an hour until doubled in size.
Finely chop all the vegetables and melt 60 grams of the butter over med-high heat. Sauté the vegetables in the butter for 7-8 minutes, until softened. Add the Herbes de Provence and sauté for another minute more. Remove from heat.
Roll the dough out, on a lightly floured surface, into a 45cm x 35cm (18in x 14in) rectangle.
Spread the reserved 30 grams of room temperature butter over the dough. Spread vegetable sauté evenly over dough.
Cut dough into 8cm (3in) strips. Stack strips into an even pile, and cut into squares. Place squares, one pile at a time, vertically into a loaf pan.
Tip: If you have extra dough, use a smaller loaf pan or a large cupcake pan for the remaining squares.
Cover loosely with plastic wrap and let rise for about an hour.
Preheat oven to 190 Celsius. Bake for 20-28 minutes, until golden brown.