1Heat oil in a 5- to 6-quart heavy pot over moderately high heat until hot but not smoking, then sauté onion, stirring occasionally, until golden, about 6 minutes. Add garlic and sauté, stirring, until golden, about 1 minute. Add tomatoes with juice, water, sugar, and salt and simmer, uncovered, stirring occasionally, until thickened, about 30 minutes. Stir in basil and remove from heat.
2Break up eggs with a wooden spoon in a medium bowl and stir in water until combined (don't beat). Sift in flour and salt, then stir batter until just combined. Force through a medium-mesh sieve into another bowl.
3Lightly brush an 8-inch nonstick skillet with melted butter and heat over moderate heat until hot. Ladle about 1/4 cup batter into skillet, tilting and rotating skillet to coat bottom, then pour excess batter back into bowl. (If batter sets before skillet is coated, reduce heat slightly for next crêpe.) Cook until underside is just set and lightly browned, about 30 seconds, then invert crêpe onto a clean kitchen towel to cool completely. Make at least 11 more crêpes in same manner, brushing skillet with butter as needed and stacking crêpes in 3 piles.
