Preheat oven to 350 convection bake setting. (375 without convection)

In a mixer, beat the cooled brown butter with both sugars 2 minutes.

Add egg and yolk and beat until creamy. Add vanilla.

Add all the dry ingredients and mix just to combine.

Weigh dough into 70 gram mounds and form them int balls. Use a wooden spoon to push the centers in like a thumbprint cookie. This will later hold the lemon curd.

Freeze a few hours and bake on parchment lined sheets for approx 12 minutes.

Let cool on sheets.

Grate zest from lemons to equal 2 tablespoons. Cut lemons and squeeze to get 1 cup lemon juice.

Beat butter and sugar with a hand mixer on medium until blended. Add eggs, 1 at a time, beating just until blended after each addition. Gradually add lemon juice to butter mixture, beating at low speed just until blended after each addition, then stir in zest. Mixture may look curdled.

Transfer mixture to a large saucepan. Cook over medium-low heat, whisking constantly, 14 to 16 minutes.

Place plastic wrap directly on warm curd (to prevent a film from forming), and chill at least 4 hours.

Place water, sugar, and corn syrup in a medium pot. Stir to combine.

Place a candy thermometer in the pot and heat over medium-high.

Do not stir anymore!

Place egg whites and cream of tartar in the bowl of a stand mixer. Beat to soft peaks (3-4 mins.) while sugar is heating. Then shut mixer.

As soon as the sugar reaches 240°F, remove it from the heat.

Turn mixer on low and VERY slowly/carefully pour the sugar syrup into the whites in a thin stream. (Try to keep it close to the side of the bowl so it doesn't hit the whisk and splatter. Stand back a bit while doing this!

Once the sugar is all in, turn to medium/high and whip 6 mins. until thick and fluffy like fluff!

Add in vanilla and whip 2 more mins.

Use right away or store for up to 2 weeks at room temperature covered well.