For the Lemon Curd

• Add all ingredients minus the butter to a medium sized sauce pan and whisk to combine.
• Cook over medium heat while stirring constantly.
• After 5-7 minutes, the mixture should begin to bubble and thicken enough to coat the back of a wooden spoon. 
• Remove from heat and stir in the butter until melted and fully combined.
• Pour the curd through a fine mesh sieve to remove the bits of lemon zest and any stringy egg whites.
• Press plastic up to the surface of the lemon curd to prevent a skin from forming and place it into the fridge to chill until ready to serve.

For the Lemon Poppyseed Cupcakes.

• Preheat the oven to 350 and line 2 cupcake pans with 18 total cupcake liners.
• In the bowl of your stand mixer add the sugar and lemon zest. Massage the zest into the sugar for 1-2 minutes to release the oils from the zest.
• Add the dry ingredients to the sugar – flour, cornstarch, baking powder, baking soda, and salt. Whisk to combine. 
• Add the cubed butter and oil and cream on medium high speed for 3-5 minutes until it’s well combined and resembles wet sand. Scrape down the bottom and sides of the bowl as needed.
• In a large liquid measuring cup, whisk together the water, vinegar, sour cream, eggs, egg yolk, vanilla, and lemon extract paste.
• With the mixer running on low speed, slowly pour in the wet ingredients, then continue to mix until fully combined. 
• Add the poppyseeds and do a final mix of the batter by hand with a rubber spatula.
• Fill the cupcake liners half full, then bake at 350 for 15-16 minutes, or until a toothpick comes out mostly clean with a few moist crumbs attached. 
• Let cupcakes cool completely. 

For the Lemon Cream Cheese Frosting

• In the bowl of a stand mixer with the paddle attachment, cream the butter and cream cheese on medium high speed for 10 minutes. Stop the mixer every 2-3 minutes to scrape down the bottom and sides of the bowl.
• Add the powdered sugar half at a time (2 1/2 C at a time) and mix on the lowest speed for 3 minutes after each addition. Again, scrape down the bottom and sides of the bowl as needed.
• Add the lemon zest and vanilla and mix to combine.
• Warm the lemon juice in the microwave for 5-7 seconds or until it is slightly warm to the touch, but NOT hot! Add it to the frosting 1 TBSP at a time until you reach your desired consistency.
• Pipe the frosting onto the cooled cupcakes using a large round tip. Leave a well in the center of the frosting and then fill that with the chilled lemon curd. 
• Top with extra poppyseeds and serve immediately.