Preheat oven to 325; grease and flour a Bundt pan.
Mix the softened margarine/butter and sugar until fluffy, then mix in the eggs one at a time, beating thoroughly after adding each one.
Add the dry ingredients, alternating with the 1 cup of buttermilk .
Put your lemon zest and lemon juice in last and mix well.
Pour into the Bundt pan and pop in the oven, baking for approximately 45-50 minutes.
Perform the "toothpick" test to make certain it is done but don't overcook !
While cake is cooking, prepare glaze by combining all ingredients in a small bowl and set aside. If glaze thickens too much to spread while standing, just add a few drops of lemon juice or milk to thin it down again.
Allow cooked cake to cool on a rack for about an hour.
Run a knife around cake in pan for easier removal.
Invert the cake out on a large plate and then poke it all over with a skewer or long tined fork.