Place flour in bowl and add egg and egg yolk. Whisk in milk. Beat until it is a thin cream and set aside for 4 hours.
Melt jelly over low heat. Mix port and gelatin in a separate bowl and add to jelly. Remove from heat and cool.
Melt butter in crepe pan on medium-high heat and add this to the pancake batter. Whisk thoroughly. Pour a thin layer of batter into pan and let cook until top layer becomes waxy. When pancake is lightly browned on bottom, flip it to cook other side. Transfer to a warm plate, second cooked side up, and repeat with remaining batter. Top crepes with 1 tablespoon of jelly filling. Roll up and dust with powdered sugar.