In a small bowl, stir together the warm water and sugar until the sugar dissolves. Stir in the yeast and allow this to sit for 6-8 minutes (it should activate and will look foamy). In a large bowl, stir together the flour and salt. Stir in the yeast mixture and 1 tablespoon melted butter until a loose dough ball forms. Turn out onto a lightly floured counter and knead for 4-6 minutes, until the dough begins to become elastic. Place in a lighlty oiled bowl, cover and allow to rise for an hour. During this time, make your lavender sugar if using.
The dough should just about double in size. Punch down and roll out on a lightly floured surface so that it’s about 1/4-inch thick. Cut into triangles, squares or other fun shapes. In a large, heavy pot, heat enough oil, so the sopapillas can float to around 350°F - 375°F. Fry the sopapillas until browned, about 1-2 minutes. Then flip so that each side cooks. Remove to a plate lined with paper towels to remove excess oil. Brush with remaining 1 tablespoon melted butter then dust with lavender sugar or cinnamon sugar.