Can a small 35cl bottle be brought back to the US in my luggage?
Yes, as long as you check your bag.
For carry-on luggage on planes, all liquids must be in containers of 3 ounces or less, in a 1 quart ziplock bag, with only 1 bag per passenger (3-1-1). In Europe, they use 100 ml instead of 3 ounces.
Liquids that cannot meet these requirements (such as your 35 cl bottle, which would be 350 ml), must be in your checked luggage. There is no limit to the size of liquids in checked luggage. If you are going to do this, bring stuff (such as bubble wrap and ziplock bags) to pack the bottle in, so it and your clothes and possessions are protected.