For example would it be okay to eat a wine sauce or beer battered fish.
I'm unsure as the alcohol has been cooked therefore you wouldn't get drunk.
The alcohol is still retained even after cooking, albeit in smaller amounts:
A study by a team of researchers at the University of Idaho, Washington State University, and the US Department of Agriculture's Nutrient Data Laboratory calculated the percentage of alcohol remaining in a dish based on various cooking methods. The results are as follows:
alcohol added to boiling liquid and removed from heat: 85% alcohol retained
alcohol flamed: 75% alcohol retained
no heat, stored overnight: 70% alcohol retained
baked, 25 minutes, alcohol not stirred into mixture: 45% alcohol retained
And alcohol in small amounts is still prohibited:
“Every intoxicant is unlawful and whatever causes intoxication in large amounts, a small amount of it is (also) unlawful.” (Sunan Ibn-Majah)
Prohibition of Wine is not dependent on it being intoxicating, rather wine is ritually unclean in itself:
الخمر والميسر والأنصاب والأزلام رجس من عمل الشيطان فاجتنبوه لعلكم تفلحون
Wine, gambling, altars and divining arrows are filth, made up by Satan. Therefore, refrain from it, so that you may be successful.
قوله تعالى : رجس يدل على نجاستها ; فإن الرجس في اللسان النجاسة
The Saying of Allah: رجس is evidence that wine is unclean, because رجس means نجاسة
So its use in food is forbidden, regardless of whether it is able to cause drunkenness.
The Prophet ﷺ commanded the Muslims to wash any pots and utensils that may be contaminated with wine, if there is no alternate to using them:
عن أبي ثعلبة الخشني أنه سأل رسول الله صلى الله عليه وسلم قال إنا نجاور أهل الكتاب وهم يطبخون في قدورهم الخنزير ويشربون في آنيتهم الخمر فقال رسول الله صلى الله عليه وسلم إن وجدتم غيرها فكلوا فيها واشربوا وإن لم تجدوا غيرها فارحضوها بالماء وكلوا واشربوا
Abu Tha’labah al-khushani said that he asked the Messenger of Allah(ﷺ):
"We live in the neighbourhood of the People of the Book and they cook in their pots(the flesh of) swine and drink wine in their vessels."
The Messenger of Allah(ﷺ) said: "If you find any other pots, then eat in them and drink. But if you do not find any others, then wash them with water and eat and drink (In them)."
The Prophet also commanded wine to be spilled and wasted, and did not allow any benefit to be derived from it, neither sale nor gift.
So consuming food in which wine been purposefully added is not permitted.