Proof the yeast: Warm buttermilk to 110 degrees. Sprinkle yeast and a pinch of sugar over it and let sit 8 to 10 minutes until foamy.
Make the dough: Whisk in eggs, melted butter, vanilla, remaining sugar, and salt. Add flour gradually and stir until a soft dough forms. Knead on a floured surface for 5 minutes until smooth.
First rise: Place dough in an oiled bowl, cover, and let rise at room temperature for 1 to 1.5 hours until doubled.
Cut the squares: Roll dough to 1/2 inch thickness. Cut into 2 to 3 inch squares. Rest on a floured tray for 15 minutes.
Fry: Heat oil to 360 to 370 degrees. Fry 3 to 4 squares at a time for 1.5 to 2 minutes per side until deep golden. Do not crowd the pot.
Finish: Drain on paper towels and dust immediately with powdered sugar. Or drizzle with the glaze made by whisking powdered sugar, milk, and vanilla until smooth.
