Poppy seeds are widely used as a spice and decoration in and on top of many baked goods, they can also be made into a paste and used as a filling in pastries. The tiny black poppy seed is less than a millimeter in size and it takes about 3,300 poppy seeds to make up a gram. Poppy seeds are a nutritionally dense spice with high levels of essential minerals calcium, iron, magnesium, phosphorus and potassium.