*Flour should be a mixture of unbleached white bread flour with 2 generous handfuls of buckwheat flour, sifted together. If you can't find the buckwheat flour, don't worry about it. For the dough: Stir together the yeast and a handful of flour in enough water to make a runny batter. Leave for 1 hour. Warm the remaining flour in the oven, mix in salt and make a well in the middle. Pour in the yeast mixture and add enough tepid water to make a moist dough. Knead for 10-12 minutes on a lightly floured surface. Leave to rise in a large floured bowl covered with a dampened cloth. When the dough has doubled in size, turn out onto a floured work surface, punch down and flatten the dough out. Add the grattons (see immediately below for how to make them). Preheat the oven to 450F/250 °C. For the grattons: Cook the meat, fat and wine over a *very* gentle heat in a heavy covered saucepan. Press down on the meat several times during cooking to render up as much fat as possible. After 1 1/2 - 2 hours, pour the liquid off through a strainer. (It can be used instead of olive oil for cooking, and often was, in Provencal cooking.) Crisp the diced meat over higher heat, straining off any liquid fat when necessary. To make the fougasse, make the bread dough, and after the first rising mixin the grattons. Then, with a knife, cut through the dough first one way, then another. Reform into a ball and repeat. Gather the pieces together into a mass, divine in two and form into two flat loaves, slashed straight through their thickness in numerous places. Spread the holes wider with your fingers. (You are striving for an effect like a flat sheet of bread with holes like those of a slice of swiss cheese.) Brush the top with the egg yolk and bake on a hot metal sheet fgor 30-35 minutes until crisp and golden. Serve warm with a bitter salad like endive or dandelion. Nb: this is a very rich bread ++ more like a salty shortbread than anything else. But *very* good.