Place the flour in a bowl and add the egg; stir to combine. Gradually whisk in the beer until the batter is smooth. Season with salt and pepper. Cover and chill for 30 minutes to rest.
To Cook
Remove the pineapple rings from the can and set them aside to drain.
Preheat the oil to 350 degrees F (180 degrees C). This can be a deep or shallow fry, thus can be done in a pot or skillet.
When the oil is hot and the batter has rested for 30 minutes start making the fritters.
Dip the pineapple in the beer batter and gently add to the preheated oil. When browned on one side turn and cook the other side until brown.
Move the pineapple fritter to a cooling rack and immediately dust with the dessert rub. Repeat the cooking process until all the pineapple is cooked. Serve while still warm.