With a mixer, blend sugar and oil together until smooth.
Gradually add egg and beat for 1 minute on medium speed.
Stir in vanilla extract.
In a separate bowl, add flour, baking powder, baking soda and salt. Mix well.
Alternate adding dry ingredients to wet ingredients with buttermilk. Use a spatula and scrape the edges. The batter will be thick, but try not to over mix.
Add raspberries and stir gently.
Gently fold in chocolate chips.
Scoop batter into lined muffin tins (ad), filling them to the very top. Sprinkle batter with sugar.
Bake at 425 degrees for 5 minutes, then lower the temperature of the oven to 375 degrees and bake for 15 to 20 more minutes. Oven temps may vary, so check frequently to make sure muffins are not over baked. They should spring back to the touch in the middle when done.
Cool muffins for 5 minutes before serving.
Notes
Ovens vary, so check to see if you need to increase baking time.
Store leftover muffins in the refrigerator.
Freeze leftovers muffins for up to 3 months. Thaw overnight in the refrigerator for best results.