Can I use leftover cooked rice in place of rice flour in a recipe for the filling of Rice Flour Tarts?

I'm not sure about that recipe, but here's one for rice tarts using cooked rice (read the directions)

Rice Tarts

Ingredients

2 oz butter

2 oz lard

8 oz plain flour

1 tbsp cooking wine

1 tbsp cream or 1 tsp milk

1 tbsp water

1 oz sugar

Filling

5 oz rice

1½ pt milk

2 eggs, separated

2 oz sugar

Pinch of cinnamon

Jam

1 oz chopped nuts

Preparation

Grease an 8 x 11 x 1 inch baking pan thoroughly.

Rub the butter and the lard into the flour. Add the liquids and sugar and knead into the dough. Chill thoroughly.

Meanwhile, cook the rice with milk until creamy.

Add the egg yolks, sugar and cinnamon to the rice mixture and fold in the stiffly beaten egg whites.

Roll out the dough and use it to line the pan. Cover the base with jam and spread the mixture over the top.

Sprinkle with the chopped nuts and bake in a moderate oven (350°F) for about 45 minutes.

Serve hot or cold, with cream or jam sauce.

as long as you don't mind bits of rice in your tarts, yes, it should be fine. looks like it will be similar to rice pudding.

the answer is a no to that.