In a bowl sift together all purpose flour, salt, baking powder and baking soda. Set aside.
In the steel bowl of your stand mixer or using your hand mixer beat together oil and sugar till smooth.
Add vanilla, greek yogurt and mix till combined.
Now add the lemon juice and lemon zest and mix.
Add the flour mixture alternating with milk, starting and ending with the flour.
Pour batter into cupcake liners till 2/3 full
Bake at 350 F degrees for 16-20 minutes or till a toothpick inserted in the center comes out clean.
Place the cupcakes on wire rack to cool completely before you frost them.
Frosting
In the steel bowl of your stand mixer fitted with paddle attachment or using your hand mixer beat together softened cream cheese and greek yogurt till smooth.
Add lemon extract and mix.
Start adding powdered sugar, 1/2 cup at a time beating till it's fully incorporated and then add more.
Place the frosting in the refrigerator for around 1 hour. This will thicken the frosting.
Pipe the frosting on cupcakes. If it looks too thick, beat it for few seconds and it will be good to go.