Preheat oven to 425°F (220°C).

Mix flour, baking powder, baking soda, salt, sugar, parmesan, sun-dried tomatoes, and seasonings in a bowl.

In another bowl, combine buttermilk, sun-dried tomato oil, sour cream, and egg yolk.

Add wet ingredients to dry ingredients, mixing until just combined.

Whip egg whites to soft peaks and gently fold into the batter last.

For the topping, mix bread crumbs, flour, seasonings, and parmesan. Add cold butter last and mix until crumbly.

Fill muffin tins with batter and top with the crumb mixture.

Bake at 425°F for 5-7 minutes, then reduce to 350°F and bake for 20 minutes more.