Preheat oven to 400 degrees. Line a baking sheet with parchment paper or a silicone liner, set aside.
In a mixing bowl whisk together flour, sugar, poppy seeds, baking powder, baking soda and salt for 20 seconds, set aside.
Add butter to flour mixture and cut into flour using a pastry cutter or fork until it resembles coarse meal, make a well in center of mixture. Chill mixture while preparing cream mixture.
In a small mixing bowl whisk together 1/2 cup + 1 Tbsp of the cream, lemon zest, lemon juice, lemon extract, yellow food coloring if using and egg until well combined.
Add cream mixture to well in flour mixture and stir using a spatula until it starts to come together, then gently roll mixture by hand several times until it has come together well (careful not to over work the dough or scones won't be as tender).
Pour mixture onto a floured surface, dust top lightly with flour then gently pat and shape into a 7 by 7-inch square. Cut into 9 equal squares, then cut each square in half on a diagonal to create two triangles (see photo above).
Transfer to prepared baking sheet spacing scones evenly apart, and brush tops lightly with remaining 1 Tbsp cream.
Bake in preheated oven 10 - 14 minutes until set. Transfer to a wire rack, let cool slightly then spoon lemon glaze over tops and spread to edges. Allow glaze to set at room temperature. Store in an airtight container.
For the lemon glaze: In a small mixing bowl whisk together powdered sugar and lemon juice until well combined. If needed add a little more lemon juice or a little more powdered sugar as needed.
Notes
Batter will be slightly sticky to work with but will give you moist scones in the end, if needed you can carefully wipe the knife clean with paper towels between cuts - and dust it with flour.
For a more yellow color you can tint with a few drops of yellow food coloring if desired. Add it along with lemon extract.