Heat the oven to 350 degrees.
Grease and flour (don’t skip this) a bundt pan. Turn the pan upside down and tap the sides to release any extra flour, and do this over the sink or a trash can.
Beat the sugar, margarine, extract, zest, and eggs in a stand mixer for 30 seconds, scrape the sides as needed. Beat on high for 3 minutes, scraping as needed.
Mix in the flour, baking powder, and salt. Turn the mixer on low.
Add the milk slowly, stopping to scrape the sides as needed. The dough will be a pourable consistency.
Use a rubber spatula to pour evenly into the greased and floured pan.
Bake for one hour and 10 minutes or until an inserted knife comes out clean.
Cool on a wire rack in the pan for 20 minutes before gently removing it to finish cooling right side up on the wire rack.
Use a serrated knife to cut the bottom off to make it sit flush, if needed. Clearly, this is for the baker to enjoy, slathered in extra frosting.
Make the icing: Heat the butter in a smaller saucepan until melted. Add in the powdered sugar, extract, and blood orange juice until it is a thin, drizzlable consistency. Wait until the cake is 100% cool to the touch and pour the glaze over as desired. Garnish with a blood orange slice if you like. This is why the blood orange garnish is a good idea — to cover up the well of icing!