Double the Spoonfuls

Lemon Curd (see notes)
1 Add lemon juice and butter to a medium saucepan set over medium heat. Stir until butter is melted then remove from heat. 
2 In a medium bowl, whisk eggs, egg yolks, and sugar together until smooth.
3 Slowly pour the hot liquid from the saucepan into the bowl with the eggs and sugar while continuously quickly whisking.
4 Pour the mixture back into the saucepan and set over low to medium heat. Whisk continuously for 5-10 minutes until the lemon curd starts to thicken and coats the back of a spoon. I usually find it thickens up at around 7-8 minutes.
5 Once thickened, pour the lemon curd through a mesh strainer into a medium shallow bowl, pressing down with a spatula to get as much of the lemon curd as possible into the bowl.
6 Take plastic wrap and press it directly on to the surface of the lemon curd and up the sides of the bowl. Let sit at room temperature for about 15 minutes, then set in the refrigerator to chill and continue to thicken, about 2 hours. Once chilled transfer to an airtight container and store in the refrigerator for up to 10 days.
Streusel Topping
8 In a medium bowl whisk together the flour, sugar, and a pinch of salt.
9 Add in the cold, chopped butter and use your fingers to cut in the butter until the mixture has formed into pea-sized crumbs. Set in the freezer while you prepare the muffins.
Lemon Curd Muffins
11 Preheat the oven to 425°F degrees and line a standard-size muffin or cupcake tray with 11 liners. To make homemade parchment paper liners cut 5-inch parchment paper squares and press them firmly around the bottom of a narrow drinking glass.
12 In a medium bowl, combine the sugar and lemon zest, rubbing the zest with your fingers into the sugar. Whisk in the flour, baking powder, baking soda, and salt.
13 In a separate medium bowl whisk together the eggs, melted butter, greek yogurt, and lemon juice. Slowly add wet ingredients to dry, using a spatula gently to combine, ensuring not to overmix.
14 Divide the batter between the 11 liners using a cookie scoop, filling each to the top. Cover each muffin with some of the streusel.
15 Bake the muffins for 10 minutes at 425°F degrees, then without removing the muffins from the oven, reduce the heat to 375°F degrees and continue baking for 6-8 minutes until the centers rise and a toothpick inserted in the center comes out clean.
16 Cool the muffins in the pan for 10 minutes, then remove them to a wire rack to continue cooling completely.
17 Once cool, use a pairing knife to cut a circle about 3/4 of the way down into the muffin, then remove the piece of the muffin. Fill a pastry bag with a large piping tip (or use a spoon) to fill each muffin hole with lemon curd up to the top of the hole. Enjoy immediately!