Line a baking sheet with parchment paper and set aside.

In a large measuring cup, whisk together 2/3 cup heavy cream and poppy seeds. Let sit for 10 minutes.

In a large bowl, whisk together flour, sugar, lemon zest, baking powder, and salt.

Using a box grater, shred the frozen butter into small pieces directly into the flour mixture. Alternatively, cut the butter into 1/4-inch cubes. Cut the butter into the flour using a pastry cutter or your fingers until the mixture resembles coarse crumbs.

To the measuring cup with cream and poppy seeds, add the egg, lemon juice, and almond extract. Whisk until well combined.

Pour the wet ingredients into the flour mixture. Use a wooden spoon or silicone spatula to stir until large dough crumbles form; do not overmix.

Use your hands to gently gather the dough into a loose ball. If it seems too dry and won't come together, add another tablespoon of cream. If it's too sticky (like cookie dough), add another tablespoon of flour. Transfer the dough to a lightly floured surface and press into an 8-inch round disc. Use a bench scraper or sharp knife to cut the disc into 8 triangles.

Place the scones on the prepared baking sheet. Brush the tops with a little extra cream and sprinkle with additional sugar if desired. Refrigerate the baking sheet while the oven preheats, about 15 minutes.

Preheat the oven to 400°F. After the oven reaches temperature, wait 5 more minutes to ensure it is fully hot.

Remove the scones from the refrigerator and bake for 20 to 22 minutes, until the edges are golden brown. Let the scones cool on the pan for a few minutes, then transfer to a wire rack.

For the glaze, whisk together confectioners' sugar and lemon juice until smooth. Drizzle over the cooled scones and serve.