To prepare crepes, lightly spoon flour into a dry measuring cup; level with a knife. Combine flour and next 6 ingredients (through salt) in a blender; process until smooth, scraping sides. Let stand 30 minutes.
Heat an 8-inch crepe pan or nonstick skillet over medium heat. Brush pan lightly with melted butter. Pour a scant 1/4 cup batter into pan; quickly tilt pan in all directions so batter covers pan with a thin film. Cook about 2 minutes. Carefully lift edge of crepe with a spatula to test for doneness. The crepe is ready to turn when it can be shaken loose from the pan and the underside is lightly browned. Turn crepe over, and cook 30 seconds or until center is set.
Place crepe on a towel; cool completely. Repeat procedure with remaining batter, stirring batter between crepes. Stack crepes between single layers of wax paper to prevent sticking.
To prepare filling, peel pears, reserving peels; thinly slice pears. Melt 1 teaspoon butter in a large nonstick skillet over medium-high heat. Add pear slices in a single layer to the pan; sauté 1 minute on each side or until slightly softened. Add 1 tablespoon brown sugar to pan; sauté 6 minutes or until golden. Remove pears from pan.
Add peels and remaining 7 tablespoons brown sugar to pan; cook 1 minute or until sugar dissolves, stirring constantly. Combine pear nectar, wine, and cornstarch in a small bowl; stir well with a whisk. Add nectar mixture to pan; bring to a boil. Reduce heat, and simmer 2 minutes or until thickened, stirring constantly. Strain sauce through a fine sieve, pressing on the peels to extract all of the liquid. Discard solids.
Spoon about 1/3 cup pear mixture in center of each crepe; fold sides and ends over. Place, seam side down, on a plate. Drizzle each serving with about 5 teaspoons sauce. Garnish with powdered sugar and mint, if desired.