• Preheat oven to 375 degrees F. Line a cookie sheet with parchment paper.
• Using an electric mixer, beat together butter and sugar on medium-high speed until light and fluffy, about 2 to 3 minutes.
• Beat in egg yolks and vanilla extract. Add flour and salt and mix until incorporated and dough comes together in a ball. If desired, chill for 30 minutes.
• Form dough into 1-inch balls (make sure they’re perfectly round), and arrange on prepared cookie sheet. Use a ½ tsp. measuring spoon to create perfectly circular craters in the center.
• Bake cookies for 8 to 10 minutes. Remove cookie sheet from oven. If indentations look shallow, further define them again and fill each with about 1/2 tsp of lemon curd.
• Bake for an additional 3 to 4 minutes, or until curd melts slightly and edges of cookies are lightly golden. Cool. Dust with powdered sugar, if desired.

Homemade Lemon Curd Instructions

• Melt butter in medium glass bowl in the microwave. Add sugar and stir. Microwave 1 minute.
• Add lemon juice and lemon zest. Microwave 2 minutes.
• Beat eggs and yolks until smooth. Pour out about 1/3 cup of hot lemon butter mixture into a 1 cup measuring cup.
• Add in about 1/4 of the egg mixture. Stir constantly, then pour into the bowl with the rest of the lemon mixture. Stir, then microwave for 1 minute.
• Repeat process, tempering eggs with a small amount of lemon mixture so that the eggs don’t cook. Stir after each 1 minute interval in the microwave. Continue until all of the eggs are mixed in.
• Microwave 2 minutes, stopping at 1 minute to stir again. Add in vanilla extract.
• Run mixture through strainer, if desired. I like to do this when the lemon curd is hot because it’s quick & easy. Straining yields a lovely smooth lemon curd, so I highly recommend it.
• Transfer lemon curd to jars and refrigerate. Curd will thicken upon cooling.