Preheat over to 350°F. Cream the butter with sugar. Beat in the evaporated milk to the butter/sugar mixture. Beat eggs into the mixture. Beat in the rice flour, baking powder and vanilla bean paste.
Pour batter into a 9 x 13-inch pan. Bake for about 1 hour, until an inserted toothpick comes out clean. Cool completely before cutting into squares and serving.
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.