Mix the yeast, brown sugar and water in the bowl of a stand mixer fitted with the dough hook. Let sit for 10 minutes and allow the yeast to proof, it will foam up. Once the yeast is ready, add the eggs, salt, buttermilk, melted butter, molasses and vanilla.
Add 2 1/2 cups flour, the ginger, cinnamon, nutmeg and all-spice, mix on medium until combined. Continue adding the remaining 1/2 cup of flour slowly until it is all incorporated. Dough will be sticky. At this point begin adding a tablespoon of flour at a time until the dough pulls away from the sides and forms a smooth ball (about 4-6 minutes). If you don’t have a mixer or would rather knead the dough with you hands, place the dough on a floured surface and knead until smooth, adding a little more flour as needed (about 8-10 minutes). The dough may still be a bit sticky, but shouldn’t be overly so.
Spray a bowl with cooking spray and place the dough inside, cover with some plastic wrap on top. Let rise for 2 hours in a warm spot. When the dough is ready place the dough on a lightly floured surface and roll out into a square or rectangle.
To make unstuffed beignets: Roll to 1/4 inch thick. Use a pizza cutter, knife or pastry cutter to cut the dough into 3×3 inch squares (about 25 squares).
To make Nutella stuffed beignets: When the dough is ready place the dough on a lightly floured surface and roll out into a square or rectangle. Roll to 1/8 inch thick. Use a knife or pastry cutter to cut into 3×3 inch squares (about 50 squares).
Scoop out a scant teaspoon of Nutella and place in the middle of a square. Gently place another square on top and pinch the sides together. Fold each side in about 1/4 inch and pinch again. It is VERY important that the beignet is well sealed. If not, it could pop open while it fries and all the filling will spill out!*
Place a deep, heavy bottom pot on the stove and add enough oil to fill the pot about 1 to 1 1/2 inches deep. Turn the burner to medium and preheat the oil to 350 degrees F. I would recommend using an instant read thermometer so you know the exact temperature at all times.
Once the oil is ready, fry 4-6 beignets at a time depending on the size of your pot. Use a slotted spoon to flip them over every 30 seconds. Fry for 2-3 minutes or until golden brown on both sides. If they are taking longer than 3 minutes to brown you need to turn your burner up and make sure your oil is at the correct temperature. Remove with the slotted spoon and place on paper towels to drain. Repeat with remaining squares. Dust the warm beignets with powdered sugar on both sides.