Preheat oven to 350°F. Prepare Spool Cakes Pan with vegetable pan spray.
In medium bowl combine flour, cocoa, baking powder, baking soda and salt. In large bowl, beat butter and sugar with electric mixer until light and fluffy. Add eggs one at a time; add vanilla and mix until well combined. Add flour mixture in thirds alternating with milk, beating well after each addition. Fill cavities 2/3 full with batter.
Bake 17-19 minutes or until toothpick inserted comes out clean. Cool in pan 5 minutes. Remove from pan; cool completely.
In large bowl, beat butter and sugar with electric mixer until well combined, scraping down bottom and sides of bowl as necessary. Add vanilla and milk; beat until light and fluffy. Cut a small 3/4 in. hole in top of each cake, being careful not to cut all the way to the bottom. Spoon or pipe filling into cakes. Position cakes on a cooling grid set on a cookie sheet.
Melt candy according to package directions. Stir in oil until well combined. Pour glaze over tops of cakes. Tap cookie sheet on countertop to even out glaze. If needed, glaze can be scraped from cookie sheet, gently reheated, and repoured over cakes. Refrigerate for 10 minutes. Gently slide a spatula underneath each cake to release from cooling grid.