Heat oven to 375°F (350°F for dark or nonstick pans). Grease bottoms only of about 58 mini muffin cups. In large bowl, beat mini cakes ingredients with electric mixer on low speed 30 seconds, then on medium speed 2 minutes, scraping bowl occasionally.
Divide batter evenly among muffin cups (about half full). (If using one pan, refrigerate batter while baking other cakes; wash pan before filling with additional batter.)
Bake 10 to 13 minutes or until toothpick inserted in center comes out clean. Cool 5 minutes. Remove cakes from muffin cups to cooling rack. Cool completely, about 30 minutes.
Place cooling rack on cookie sheet or waxed paper to catch glaze drips. In 3-quart saucepan, mix all glaze ingredients except hot water. Heat over low heat, stirring frequently, until sugar is dissolved. Remove from heat. Stir in 2 teaspoons hot water. If necessary, stir in up to 1 teaspoon more water so glaze will just coat cakes.
Turn each cake so top side is down on cooling rack. Pour about 1 tablespoon glaze over each cake, letting glaze coat sides. Let stand until glaze is set, about 15 minutes.
Top each cake with candy hearts. Store loosely covered.