Preheat the oven to 400°F.Line a muffin tin with muffin liners or spray with nonstick cooking spray. In a large bowl, mix flour, pistachio pudding mix, baking powder, and salt. In a medium bowl, add oil, sugar, milk, sour cream, eggs, and almond extract. Whisk until smooth. Pour the wet ingredients into the dry ingredients. Using a spatula, stir to just combine (don't overmix).
Spoon the muffin batter into the prepared muffin tins filling ¾ full. Sprinkle with coarse sugar and crushed pistachios.
Place muffins on the middle rack of the oven. Bake for 18-22 minutes or until a toothpick comes out with just moist crumbs when poked in the middle. Let cool in the muffin tin for 10 minutes before transferring it to a cooling rack to cool completely. Store leftover muffins in an airtight container for up to 4 days.