Add the yeast, water and sugar to the bowl of a stand mixer fitted with a dough hook attachment (or use a large bowl and a hand mixer with a dough hook attachment). Let rise for 2 minutes.
Add 6 cups of the flour and salt to the bowl with the yeast mixture.
Zest the lemon and orange and add the zest to the bowl with the flour and yeast mixture.
Peel the orange and lemon and add the flesh of the fruit to your blender (be sure to remove the seeds).
Add the milk, melted butter, eggs and sugar to the blender and blend on high speed until smooth.
Add the contents of the blender to the bowl of the mixer and mix on low speed until a sticky dough forms.
Add the additional 1 to 1 1/2 cups flour as the mixer kneads the dough, 1/2 cup at a time until the dough becomes less sticky, but still soft.
Cover the bowl with plastic wrap and rise for 90 minutes.
Divide the dough into 30 equal pieces and roll each piece into a round bun shape. Place the buns on parchment paper-lined baking sheets.
Cover with a kitchen towel and rise for about 20 minutes. This is a good time to preheat your oven to 325 degrees Fahrenheit (165 degrees Celsius).
Bake the buns at 325 degrees Fahrenheit (165 degrees Celsius) for about 18 minutes, or until the buns are light golden brown on top.
Let the buns cool on the baking trays until completely cool.