This has been easier than anticipated!
(And it also helps at dealing with product variants)
Here is my Code(a simple Form):
<form method="post" action="{{ Shopify store url }}/cart/add" id="product_form_597803827251" accept-charset="UTF-8" class="product-form product-form-product-template
" enctype="multipart/form-data"><input type="hidden" name="form_type" value="product"><input type="hidden" name="utf8" value="✓">
<select name="id" id="ProductSelect-product-template" class="product-form__variants no-js">
<option selected="selected" value="7619582230579">
Default Title
</option>
</select>
<div class="product-form__item product-form__item--submit product-form__item--no-variants">
<button type="submit" name="add" id="AddToCart-product-template" class="btn product-form__cart-submit">
<span id="AddToCartText-product-template">
In den Einkaufswagen legen
</span>
</button>
</div>
</form>