Mix the flour and salt. Crumble yeast, stir in milk until smooth, knead with about 250 ml of water and the flour until smooth and then let rise for 30 minutes.
Peel the onions, cut into strips and sauté in hot oil. Then salt and pepper. Knead two thirds of the amount into the dough, possibly adding a little more flour. Let rise again for 30 minutes.
Divide the dough into three portions and shape into baguettes, toss in the remaining onions. Place on a baking sheet with baking paper and let rise for 60 minutes. Preheat the oven to 200 degrees (convection 180 degrees). Bake for about 20 minutes.