Preheat oven to 350º F. Butter a 9 x 13 pan. Cream the butter and honey in a bowl. In another bowl, mix together the flour, powder, and poppy seeds. Then add to the creamed butter mixture a little at a time in four installments, alternating with the eggs and mixing thoroughly after each addition. Pour into the pan and smooth the top. Bake for 25-30 minutes. Cool on a wire rack and cut into squares for serving.
Note: This recipe does not lend itself too well to cooking evenly, especially in the middle, so if you'd like to avoid getting the edges a bit too toasty while the middle is a bit too underdone, try small loaf pans instead!