Sounds like you were served puto. There are three variations in "Philippine Cooking in America" by Marilyn Donato. She has adapted many Filipino recipes to the ingredients available here in the States.

PUTO (Steamed Rice Cake)

2 c. Bisquick
1 c. sugar
1 c. milk
2 eggs

Mix all ingredients to a smooth consistency. Pour to muffin pans, 2/3 full. Steam in large, well covered pan with about 3 inches deep water for 15 minutes, or until inserted toothpick comes out clean. Add more water as needed during steaming period. Loosen and remove puto from muffin pans. Yields 4 dozen tiny puto or 2 dozen regular-size muffin puto.

For colored puto, divide batter to 3 bowls. Add few drops of green food color to one bowl; yellow to another, and red to the third bowl to produce a pink color. Pour to muffin pans and steam.

PUTO BULACAN (Steamed Rice Cake)

2 c. rice flour
1 pkg. dry yeast
1 c. sugar
1 c. Bisquick
2 c. warm water
1/4 tsp. anise seeds (optional)

Follow above procedure for Puto.

PUTO CHINESE (Spongy Steamed Rice Cake)

3 c. rice flour, from long grain rice
1-1/2 c. sugar
3 c. water
2 tsp. yeast
2 Tbsp. warm water

Mix rice flour, sugar and 3 cups water until smooth. In separate cup mix yeast and warm water and let stand 10 minutes. On medium-low heat cook rice flour mixture, while stirring constantly until thickened, about 20 minutes. Pour hot batter to a sieve into a large bowl then mix in dissolved yeast. Let stand for 6 to 8 hours, until bubbles appear. Pour into suitable pan lined with cheesecloth or plastic wrap. Cover and steam for 25 minutes, or until inserted toothpick comes out clean. Cool. Cut into diamond shapes. Serves 6 to 8.

Come to think of it, puto isn't very sweet (relatively speaking). If none of these recipes matches what you were served at that Filipino party, please post again. Maybe you had bibingka, a sweet rice cake?