In saucepan of boiling salted water, cook potato until tender, about 10 minutes. Drain and let cool. Cut into 1" chunks.
Meanwhile, whisk together eggs, flour, baking power, an half the salt; set aside.
In a 9" nonstick ovenproof skillet, heat half of the oil over medium-high heat; saute garlic for 1 minute. Add spinach; cook, stirring, until wilted and no liquid remains. Transfer to bowl.
Add remaining oil to skillet; cook onion, stirring occassionally, until softened, about 6 minutes. Add potato; cook, stirring, until softened and starting to brown. Stir in paprika and remaining salt. Stir in spinach and egg mixture. Transfer skillet to 350F oven; bake until firm, about 20 minutes.