For streusel: In a medium bowl, combine flour, brown sugar, zest, and poppy seeds. Drizzle with melted butter, and stir with a wooden spoon until combined. Crumble with your fingertips until desired consistency is reached.
Preheat oven to 425°F. Spray an 8-inch round cake pan with baking spray with flour. Line a baking sheet with parchment paper.
For scones: In the work bowl of a food processor, place flour, sugar, poppy seeds, baking powder, salt, and zest; pulse until combined. Add cold butter, and pulse until mixture is crumbly.
Transfer dough to a large bowl, and fold in cream, ricotta, and lemon juice, stirring until combined. Turn out dough onto a lightly floured surface, and knead briefly, just until dough comes together. (This is a soft dough.) Press dough into prepared cake pan. Turn out, and using a sharp knife or bench scraper, cut into 8 wedges. Transfer wedges to prepared baking sheet.
Sprinkle liberally with streusel, and bake until golden brown, 12 to 15 minutes.
