Preheat oven to 425 degrees F. Line two muffin tins with about 18 paper liners; set aside. Meanwhile, in a large bowl, whisk together the flour, baking powder, salt, cinnamon, orange zest, and white sugar until combined.
Add in the oil, eggs, buttermilk, orange juice and vanilla until a thick batter has formed. Batter may be lumpy; that's okay! Do NOT over-mix. Overmixing leads to very dry and tough muffins. Evenly drop heaping Tablespoonfuls of dough into the muffin tins, filling about 3/4 of the way full.
Bake for approximately 5 minutes at 425 degrees F. Then, without removing the muffins, lower the oven temperature to 375 degrees F for about 15 minutes or until the muffins are golden brown on top and when an toothpick inserted into the center comes out clean or with moist crumbs. Cool the muffins completely.
While the muffins cool, prepare your champagne glaze. In a small saucepan, bring the water, champagne and sugar to a boil. Once boiling, reduce heat to a steady simmer for 10 minutes, then remove from heat.
Dunk the tops of the muffins into the glaze, allowing excess to drip off. Return to the tin or a platter and sprinkle with the coarse sugar. Serve!