Begin by preparing your cherries. If using fresh cherries, wash them thoroughly, remove the pits, and slice them in half. In a large mixing bowl, combine the cherries with 1/2 cup of granulated sugar, cornstarch, lemon juice, and optional almond extract. Gently mix together and set aside.

In another bowl, combine 2 cups of flour, 1/2 cup of granulated sugar, baking powder, baking soda, and salt. Whisk until evenly incorporated.

Add the cold, cubed butter to the dry ingredients. Work the butter into the flour mixture until it resembles coarse crumbs.

Create a well in the center of the dry mixture. Pour in the buttermilk, beaten egg, and vanilla extract. Gently stir until just combined.

Fold the cherry mixture into the muffin batter carefully.

Prepare your muffin tin by lining it with muffin liners or greasing each cup. Fill each muffin cup about three-quarters full with the batter.

In a small bowl, mix together the remaining 1/2 cup of flour, brown sugar, cubed butter, and ground cinnamon. Crumble together to create a streusel topping.

Distribute the streusel topping over the filled muffin cups.

Bake in a preheated oven, checking for doneness with a toothpick.