• Preheat oven to 350℉. Line a 12-cup muffin tin with cupcake liners.

Streusel

• In a small bowl, combine sugar, flour and graham cracker crumbs. Cut butter in small chunks and toss with streusel ingredients. Use a fork, or clean hands, to crumble it together, breaking up the butter into small crumbly pieces. Place streusel mixture in fridge.

Cheesecake Filling

• Beat all cheesecake ingredients together until smooth. Set aside.

Muffins

• Combine 1 ¾ cup flour, baking powder, salt, ½ cup sugar, and orange zest in a bowl. Whisk to combine. In a separate bowl, combine egg, buttermilk, oil, and vanilla. Add wet ingredients to dry ingredients and stir until just combined. Do not over-beat. Place berries in a bowl (do not thaw frozen berries) and sprinkle over remaining 1 tablespoon flour and 1 tablespoon sugar. Toss together and then add to muffin mix. Gently stir just until distributed.
• Fill muffin cups with batter. Place cheesecake mixture in a zip-top bag and snip on the corner. Gently squeeze about 2 teaspoons of filling directly into the batter. It’s okay if it’s visible on the top. Evenly divide streusel topping on muffins.
• Bake for 15-20 minutes, or until a toothpick inserted in the muffin part comes out with just loose crumbs attached. Let cool for 5 minutes, then remove from muffin tin and place on cooling rack. Let cool to room temperature.