Preheat oven to 350 °F and spray or grease cookie sheets.
In a large bowl, beat sugar, oil, vanilla, and egg replacer mixture. Separately, mix together gluten-free flour, baking powder, and salt. Add this to the sugar/oil mix in the large bowl.
Roll out the dough in portions between two sheets of waxed paper, liberally dusted with rice flour below and above the dough. Using overturned glass or biscuit cutter, cut out approximately 3" diameter circles. Place circles on cookie sheets, and place 1/2 - 1 tsp jam in center of each circle. TIGHTLY pinch in the sides of each circle to make a triangle. Repeat with remaining dough.
Corn Substitutions: Corn is a common ingredient in products. Starch, modified food starch, dextrin and maltodextrin can be from corn. Consult with your physician to find out which corn derivatives you need to avoid. Many corn-free options are available in the US. Find out more about corn substitutions.
Egg Substitutions: There are many egg-free products and foods available to make your recipes free of eggs. Find out more about egg substitutions.
Gluten: Gluten is a protein found in specific grains (wheat, spelt, kamut, barley, rye). Other grains are naturally gluten-free but may have cross-contact with gluten-containing grains. Look for certified gluten-free products if you need to avoid gluten. Find out more about wheat and gluten substitutions.