Preheat oven to 375° Fahrenheit and place an oven rack in the middle position.
Add the melted butter and vegetable oil to a bowl and whisk together. Add the eggs and whisk until combined. Add the almond extract and buttermilk and whisk to combine. In a separate bowl whisk together your cake flour, granulated sugar, baking powder, baking soda, salt, and poppy seeds. Add to the wet ingredients and use a spatula or wooden spoon to fold the ingredients together gently, being careful not to overmix.
When baking muffins I find it helps to only bake six at a time in a muffin pan that holds 12. This gives the muffin tops room to rise and spread out. Line every other well in your cupcake pan with a cupcake liner and fill to the top with batter. I used an ice cream scoop to do this and it was just the right amount. Sprinkle and press several sliced almonds into the top of the batter. Bake for 13-15 minutes in preheated oven. A toothpick inserted into the center should be clean and the top should spring back when you press on it with your finger.
As soon as you remove the pan from the oven use a spoon to help you remove each muffin for the pan and place on a wire rack. They will be hot so be careful. Bake the rest of the muffins six at a time, spaced apart. Allow all of the muffins to cool completely on a wire rack before topping with the sweet almond glaze.
Almond glaze
In a small bowl whisk together powdered sugar, almond extract and heavy cream until it is smooth and pourable. Drizzle over cooled muffins and enjoy.
Notes
Store muffins in an airtight container for 2-3 days.