Preheat your oven to 350 degrees
Add 3/4 cup of sugar and 2 tablespoons of lemon zest into a large bowl
Rub the lemon zest and sugar together with clean dry hands until the sugar becomes a pale yellow and the zest is spread evenly throughout the sugar
Add 2 tablespoons of melted butter, 1/4 cup of vegetable oil, 2 large eggs, 1/4 cup of freshly squeezed lemon juice, 1 teaspoon of vanilla extract and a few drops of lemon extract and mix until smooth and pale yellow in color
Combine 1/2 teaspoon of salt, 1 1/2 teaspoon of baking powder and 2 1/2 cups of all purpose flour in a small bowl
Add half of the dry ingredients into the wet ingredients and mix to combine
Add the remaining dry ingredients and 2 tablespoons of poppyseeds into the batter and mix until all of the ingredients are fully incorporated
Prepare a baking sheet by lining with parchment paper or a silicone baking mat
Lightly dust the surface and transfer the dough onto it
Divide the dough in half and gently press both portions into rectangles that are about 8 inches long and 4 inches wide using floured hands
Brush the lemon egg wash over the entire surface of the dough
Bake at 350 degrees for 22-25 minutes or until the dough feels set to the touch and the edges are lightly golden brown
Transfer the baking sheet onto a cooling rack for 10 minutes
Carefully transfer the dough onto a cutting board using the silicone mat or parchment paper
Cut 3/4-1 inch wide strips from the dough using a sharp knife and starting at the short end and arrange the biscotti cut side down on the same baking sheet
Return the biscotti to a 350 degree oven and bake for 6-8 minutes per side
Transfer the biscotti onto a cooling rack
Make the lemon glaze by combining 1 cup of sifted confectioners sugar with 1 tablespoon of whole milk and 1 tablespoon of fresh lemon juice (add additional lemon juice, if necessary)
Dip or drizzle each biscotti with the lemon glaze and garnish with additional poppyseeds
Return the biscotti onto the cooling rack and allow the glaze to set for 20 minutes
Store in an airtight container for up to 10 days