Preheat oven to 350°F and line a muffin tin with cupcake liners.
In a bowl, whisk together flour, sugar, baking powder, salt, and poppy seeds.
In another bowl, beat the butter until creamy, then mix in eggs, lemon juice, zest, and buttermilk.
Slowly combine the wet and dry ingredients, stirring just until smooth.
Fill cupcake liners two-thirds full and bake for 18 to 20 minutes, until golden and a toothpick comes out clean.
While the cupcakes cool, beat the butter for the frosting until light and fluffy.
Slowly add powdered sugar, honey, and vanilla, mixing until smooth. Add heavy cream one tablespoon at a time until the frosting is creamy and spreadable.
Frost the cupcakes and serve.