Combine eggs and sugar in a large bowl; set aside.
Beat butter and liqueur or syrup until fluffy using an electric mixer; add to egg mixture. Add baking powder, salt and all except 2 tablespoons flour. Beat until well-blended and no lumps remain; set aside.
Combine berries and remaining flour; toss to coat berries. Gently fold berries into batter. Pour into a greased and floured Bundt pan.
Bake at 325 degrees until a wooden pick inserted into center comes out clean, about one hour.
Remove from oven and let cool in the pan for 20 to 25 minutes; turn out onto a wire rack to cool completely. Sprinkle top of cake with powdered sugar.