What to call this utensil
I'm unsure about an English term, but in German it is a "Quirl", related to the "whorl" of twigs on a stem it was originally made of - for example from old Christmas trees:


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Later versions mimicked this with a star-shaped wooden or porcelain "head" on a wooden handle,

 

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the plastic head is a more modern twist:


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In Central Europe you should be able to buy them from either kitchen stores or - if regionally less common - from various online retailers.