Preheat oven to 325°F. Grease and line bottom and sides of a 10-inch baking pan. Cream butter and sugar until light and fluffy. Do not over cream or cake will deflate. Stir in almond flour and vanilla bean paste. Stir in eggs one at a time, then fold in lemon zest, polenta, baking powder and salt. Pour batter into prepared pan and bake 75-90 minutes, rotating at 40 minutes. Check cake for doneness by inserting a skewer into center. Remove from oven and cool before serving.
Serve with a dollop of crème fraiche and strawberries.