Preheat oven to 350 degrees F. Line a large baking sheet with parchment paper.
Mix the flour, baking powder and salt together in a bowl and set aside.
In a mixing bowl, beat the eggs until foamy. Add sugar and beat for about 30 seconds, then beat in the melted butter (or oil), corn syrup, lemon paste and lemon zest.
Add the flour mixture and stir until blended.
With damp hands, shape the dough into a log about 11 inches long and 1 inch high directly on a baking sheet.
Bake on center rack for 30 minutes. Let cool on baking sheet for about 10 minutes, then transfer to a cutting board and cut into about 16 to 18 slices.
Reduce oven heat to 300 degrees F.
Stand biscotti bake on the baking sheet and bake at 300 degrees F for about 25 minutes. Let cool.
To make the glaze, put the powdered sugar in a bowl and slowly trickle in lemon juice, stirring constantly, until you have a pourable glaze. Drizzle over the biscotti and allow it to set.
You can leave the biscotti as is, or melt white candy melts or white chocolate and add a drizzle of that too!