01 -
Preheat oven to 350°F. Line your 8x8 pan with two strips of parchment crisscrossed.
02 -
Mix together the butter and sugar until fluffy, about 3 mins. Stir in salt and flour. Press dough evenly into pan.
03 -
Pop into oven for 15-18 mins until golden around edges. Put aside to cool down a bit.
04 -
Whisk sugar and eggs until slightly thick, about a minute. Add zest, juice, and flour. Spread over the warm crust.
05 -
Bake again 18-20 mins until it's golden and set. Cool totally, then slice into 16 pieces.