Preheat oven to 350F. Butter an 8 x 4-inch loaf pan.
Place almonds and 1/2-cup of flour in bowl of a food processor and grind until a fine meal is formed; the flour will prevent the nuts from turning oily. Add remaining rice flour, baking powder, salt and 2 teaspoons of the poppy seeds; process briefly.
Combine yogurt, water, egg, egg white and oil in a 2-cup measuring cup.
With processor motor running, pour liquid ingredients through feed tube over flour mixture, processing just long enough to mix.
Transfer batter to prepared pan. Sprinkle with remaining poppy seeds, and bake for 55 minutes. Turn out onto a rack to cool. (Bread slices best after several hours, or the next day).
Makes one 18-ounce loaf (18 slices).