Preheat the oven to 425°F and grease a muffin tin. 

For the Cinnamon Streusel Topping:

1. In a small bowl, mix the sugar, flour, cinnamon, and salt.
2. Using a fork, blend in the margarine until the mixture resembles the texture of sand. Set aside.

For the Cinnamon Swirl:

1. In a small bowl, combine the coconut sugar (or brown sugar) with the cinnamon. Set the mixture aside.

For the Muffins:

1. For the wet mixture: In a small bowl, mix the plant-based milk, fresh lemon juice, golden flax meal, and vanilla extract. Let it sit for 5-10 minutes, allowing the milk to curdle.
2. For the dry mixture: In a separate bowl, combine the flour, salt, and baking powder.
3. In a stand mixer or large bowl, cream the margarine and sugar together until light and fluffy.
4. Add half of the dry mixture to the creamed margarine and sugar and gently mix until halfway incorporated. Next, add half of the wet mixture and mix before adding the rest of the dry flour mixture while finishing with the wet mixture. The batter should be thick and consistent when thoroughly combined.
5. Spoon the batter into the prepared muffin tin, filling the muffin cups halfway full, and sprinkle with the cinnamon swirl mixture. Next, finish with the rest of the batter and sprinkle the cinnamon streusel topping on top.
6. Bake the muffins for 5 minutes at 425°F, then lower the oven temperature to 375°F. Continue baking for another 12-15 minutes until the muffins are golden brown, and a toothpick inserted comes out clean with a few crumbs attached.