Savory buttermilk brioche with a pear rosemary meat filling

Name: Savory buttermilk brioche with a pear, rosemary & meat filling
Ingredients: for the dough:; 250 grams AP wheat flour + some for kneading; 1 teaspoon dry yeast; 2-3 pinches salt; 1 teaspoon sugar; 100 milliliters buttermilk; 50 grams butter, melted and at room temperature; 2 eggs; 1 egg yolk for glaze; some sea salt / fleur de sel to sprinkle; 1 handful sesame seeds to cover buttered baking tray (optional); for the filling:; 250 grams meat from raw coarse pork sausage; 1/2-1 pear (ripe, but firm); 1 tablespoon balsamico bianco vinegar; 1 tablespoon finely chopped fresh rosemary; 2 spring onions, chopped; 2 slices bacon or other raw ham, finely chopped; 10 grams pistaccios, coarsely chopped; 1 egg