• Using pastry brush, oil the bundt cake pan and sprinkle it with fine dry bread crumbs so that the cake doesn’t stick. Set aside.
• In a large bowl, combine flour, cornstarch, sugar, baking powder and salt.
• In another bowl, mix eggs with oil, milk, lemon juice, rum, vanilla extract and rum flavoring. 
• Mix the dry ingredients and the wet ingredients and beat on medium speed for 1-2 minutes, or until the batter is smooth.
• Pour the batter into prepared bundt cake pan and bake in 350°F (175°C) oven for about 20 minutes. Rotate the cake, set the temperature to 300°F (150°C) and bake for another 20 minutes. Check with wooden skewer for doneness.

Rum Butter Sauce

• In a small saucepan, cook butter, water, sugar, rum and vanilla for a few minutes or until sugar dissolves.
• After the cake has cooled a little, use a skewer to poke lots of holes (at least 20) all over the cake. SLOWLY pour the sauce over the cake. Let it rest until the sauce is absorbed, about 10 minutes.
• At this point either serve the cake, or cover it and until serving.