Makes 8 large buns. Make the dough 1-3 days ahead of baking.   Dough: 380g AP flour 20g whole flour (or more AP flour) optional: 10g dried onion flakes (1 heaping tablespoon) 3g dry yeast 20g sugar (I reduce 10g and add 30g malt syrup) 9g salt 275g room temp water 15g butter, cubed Onion mixture: 2 large onions (350g), finely diced 15g butter (~1 tbpsn) 20g poppy seeds 1/2 tsp salt