Preheat oven to 350F. Lightly grease an 8" square baking pan and line with a parchment paper sling, leaving two flaps at least an inch over two sides of the pan (this will help you lift the bars out after they set).

Place all dry crust ingredients (sugar, flour, and salt) in a food processor, and pulse a few times to mix well. Add softened butter and pulse until uniform crumbs form (you can also mix all ingredients together by hand or using a mixer on low if you prefer).

Sprinkle crumbs across the bottom of the greased and lined pan, working any remaining dry clumps into the dough by hand (if dough has come together into a single mass, just break it up into crumbs by hand in the pan). Press dough crumbs firmly into an even layer in the bottom of the pan and one inch up the sides.

Bake crust at 350F for 20-25 minutes until golden brown.

While crust bakes, make the filling. Measure all dry filling ingredients except the coconut (sugar, cornstarch, and salt) into a small bowl and whisk until well combined.

In a medium bowl, whisk together all wet filling ingredients (lemon zest, lemon juice, ricotta, and eggs) until well combined.

Thoroughly whisk dry mixture into wet mixture until uniform and smooth, with no visible clumps of ricotta or dry ingredients remaining. Once smooth, stir in the coconut if using.

Remove crust from the oven when ready and reduce oven temperature to 325F.

Stir filling mixture again if it has sat for any amount of time, then pour slowly onto hot crust.

Keeping pan level, place it back in the oven and bake for 18-22 minutes, or until the filling looks just set and doesn't ripple when the pan is gently shaken. If using coconut, increase bake time to 20-24 minutes. To prevent cracking after cooling, make sure to not overbake bars.

Cool pan on a wire rack for at least 2 hours, or until it's room temperature, then move to the refrigerator to chill for at least one hour.

Once bars are chilled, loosen the edges of the bars from the pan, gently pull up on the sling to remove the whole square from the pan at once, and place it onto a cutting board. Slice bars to desired size (we recommend 2" squares). For best results, clean knife with warm water between cuts.

If desired, dust with powdered sugar for decoration. Bars can be kept up to 1 week stored in an airtight container in the refrigerator.