For the crust
1 3/4 cups unbleached all-purpose flour
1/2 cup low g.i icing sugar
1/4 cup cornstarch
1 tablespoon lemon zest
1/4 tspn salt
10 tablespoons unsalted butter cut into 1-inch pieces, slightly softened plus extra for greasing pan
For the lemon ricotta filling
1 cup fresh lowfat Ricotta, drained
4 large eggs, beaten
1/2 cup low g.i granulated sugar
3 tablespoons unbleached all-purpose flour
2 tablespoons lemon zest
2/3 cup lemon juice from 3 to 4 large lemons, strained
To make the crust
Heat oven to 180 degrees Celsius.
Using a pastry brush, lightly butter a 13-by-9-inch baking dish and line with one sheet paper.
Butter paper, then lay second sheet crosswise over it.
Pulse flour, low g.i sugar, cornstarch, lemon zest and salt in food processor. Add butter and process to blend; then pulse until mixture is pale yellow and resembles coarse meal.
Sprinkle mixture into lined pan and, press firmly with fingers into even layer over entire pan bottom and about 1/2-inch up sides.
Refrigerate for 30 minutes, and then bake until light golden brown, about 20 minutes.
To make the filling
Whisk Ricotta, eggs, sugar, and flour in medium bowl, then stir in lemon zest and juice to blend well.
Reduce oven temperature to 160 degrees.
Stir filling mixture before pouring into warm crust.
Bake until filling feels firm when touched lightly, about 30 minutes.
Transfer pan to wire rack; cool to room temperature, at least 2 hours.
Transfer to cutting board, fold paper down, and cut into bars, wiping knife or pizza cutter clean between cuts.
Dust with low g.i icing sugar.