In a large bowl, mix together flour, sugar, and lemon zest until combined. Whisk in egg, milk, and vanilla extract until smooth. Let rest for about 5 minutes.
Place a heavy skillet over high heat for 2 minutes. Reduce heat to medium low and add 1/2 teaspoon of butter.
Once butter is melted and sizzling, add 1 tablespoon of batter to form a circle. Once bottom is golden and bubbles start forming on top, 40 seconds-1 minute, flip to cook other side. Cook until golden, another minute. Remove to plate and repeat with remaining batter, adding more butter as needed.
Serve warm with raw sugar and lemon.