In a large mixing bowl, combine butter, oil and sugar.
¼ cup butter, ½ cup sugar, 1 tablespoon oil
Mix in lemon zest, lemon juice, egg, milk and vanilla
1 tablespoon lemon zest, 2 tablespoons lemon juice, 1 egg, 1 cup milk, ½ teaspoon vanilla
Mix in poppy seeds, whole wheat flour, baking powder and salt. Mix just until combined.
2 Tablespoons poppy seeds, 2 cups white whole wheat flour, 2 teaspoons baking powder, ½ teaspoon baking soda, ¼ teaspoon salt
Measure into paper lined or greased muffin tins.
Bake at 400 degrees for 12-14 minutes.
Let cool slightly for 1-2 minutes and then remove from tin. Continue cooling on a baking rack.
Glaze
Mix powdered sugar and lemon juice together.
1 cup powdered sugar, 1-2 1ablespoons lemon juice
While muffins are still warm, but not hot drizzle with glaze.
Notes
Use softened, but not melted butter
The mixture may look slightly curdled when adding the lemon juice and milk. This is okay!
To save time (and a bowl) I will often add the flour, baking powder, baking soda and salt right to the wet ingredients. I then reach in with a small spoon (with the mixer OFF) and just give the dry ingredients a quick stir. This mixes up the salt and baking powder/soda so it's distributed throughout the flour.
Once the flour is added, just mix with the mixer a few times. You want the flour to just be barely mixed into the wet ingredients.
Turn the mixer off and then fold everything together with a spatula. You don't want to overmix or the muffins will become tough.
Oven temperatures vary, so baking times may vary.
Check muffins at 12 minutes and test with a toothpick. If needed, bake for 1-2 additional minutes.
Paper liners may be used for making the muffins or you can simply spray the muffin tin with nonstick spray