Step 1

Preheat oven to 350˚ F.  Line a sheet pan with parchment paper.

Step 2

By hand or with a stand mixer: Combine the flour, sugar, salt and baking powder in a large bowl. Add the butter. With your finger tips (or paddle attachment if using a mixer) rub the butter into the flour mixture; the texture should look like coarse crumbs.

Step 3

Add the egg yolks, milk, vanilla extract and lemon zest, if using. Mix until the dough holds together (it should be smooth- not sticky or dry). Roll the dough into a ball, cover with plastic wrap and chill for 30 minutes- 1 hr or overnight.

Step 4

Cut the dough into 8 equal pieces. Roll into (8x) 5-inch long logs. Cut the logs into (24x) 1 1/2-inch pieces, like gnocchi but bigger.

Step 5

Dunk the dough in the reserved egg whites and then roll in the sesame seeds. Place onto the sheet pan.

Step 6

Bake for 30 minutes until light golden brown.

Step 7

Once completely cool, store the cookies in an airtight container for several weeks. Freeze for up to 1-2 months.