Preheat oven to 375 degrees. Coat an 8 or 9 inch cast iron pan, glass casserole dish or round cake pan with cooking spray. Set aside.
In a large mixing bowl or the bowl of a stand mixer fitted with the bread hook, combine mashed potatoes and eggs until combined.
Add milk and vegetable oil, blending until just combined.
Sift together flour, baking powder, fine sea salt and sugar. Add to wet mixture.
After dough has come together, blend or mix for an additional 1 minute.
Turn dough into greased cooking vessel. Don't push too hard, but make sure the dough is flat, not rounded on the top. Score a large "X" in the top. Give a light dusting of cooking spray to the top of the bread.
Bake for 45-50 minutes. If the top starts to brown too much, loosely cover with a leaf of aluminum foil.
Remove and allow to cool before turning out of the baking dish. Wait for bread to nearly cool fully before slicing.
Store wrapped well at room temperature. Bread is best enjoyed within 3 days of baking.
If you've tried this recipe, come back and let us know how it was!
Bread can be well wrapped and frozen for up to 6 months. If you using skim or lowfat milk, add 1 tablespoon melted butter to account for additional fat.