Heat oven to 375°F and arrange a rack in the middle. Grease 12 muffin cups or line with paper liners. Combine sugar and lime zest in a medium bowl and rub together with your fingers until the lime zest in coated in sugar and the sugar smells like limes.
Add the flour, poppy seeds, baking powder, cream of tartar, and salt and whisk to combine.
In a separate large bowl, whisk together the almond milk, vinegar, eggs, vanilla, oil, and lime juice.
Add the flour mixture to the liquid mixture and combine with a rubber spatula until most of the flour is mixed in. Add the raspberries and gently fold them in, being careful not to break them up too much.
Divide the mixture between the muffin cups (they will be mostly full) and generously sprinkle the tops with sugar.
Bake for 20-25 minutes or until a toothpick inserted in the middle comes out clean. Remove to a wire rack and serve warm with butter.