Below I outline the fruits and vegetables which would have been grown domestically and eaten in north western Europe (France/Germany/England) by the late medieval period, or in some cases imported from southern Europe in preserved form.

The late medieval period would have been just the point before 'new world' foods found their way to Europe.

I do not include here the medieval trade in spices (which was significant). Nor do I discuss meats, fowl, fish, cereals and legumes (beans); in the main these remained relatively the same through the medieval period and are recognizable to us today, although methods of husbandry might have changed (ie forest-raised pigs vs. pasture and pen, river fishing vs. fish ponds, etc) or dominance of one cereal or legume over another based on substantial transformation of cultivation techniques between 10-13th century CE (crop rotation).

I use north western Europe as a barometer; many foods were in the mediterranean Europe centuries before the north adapted or adopted them.

Note: In [brackets] are origins, then first cultivation reference in West, then Medieval uses (medieval = high to late medieval due to documentary sources).

Fruit

Apples: [Caucasus] evidenced by Greeks and Romans; Medieval: fresh or dried; added to sauces and as fillings; added to verjuice (cooking liquid); made cider

Pears: [Caucusus] evidenced by Greeks and Romans; Medieval: like apples, eaten fresh or dried; added to sauces and as fillings; made cider

Quinces: [Caucasus] evidenced by Greeks and Romans; Medieval: preserved in honey, eaten as 'marmalade' or in sauces and stews

Plums: [European native?] evidenced by later Romans; Medieval: eaten fresh and dried; stuffing, sauces and stews

Peaches: [China via Persia] evidenced by Greeks and Romans; eaten fresh and dried; stuffing and sauces

Cherries: [West asia] evidenced by Romans; Medieval : eaten fresh and dried; preserves; stews and stuffing

Berries: [Indigenous] Late medievals created several of the cultivars we know now, including strawberries; however berries of all sorts were foraged and grow including blackberries, raspberries; eaten fresh and dried

Grapes: [West asia via Phoenicians] evidenced by earliest Greeks; Medievals fresh and dried as raisins; juice, syrup, fermented as wine and spirits; vinegar and verjuice;

Citrons (lemon/lime): [India] evidenced by late Romans; Northern Medievals imported these from the mediterranean as they did not grow domestically, and were therefore eaten dried or preserved

Oranges: [India/China] Arrived in medieval mediterranean as bitter varieties by 12th century; juiced; candied/preserved

Figs: [Not indigenous but predates Greeks] evidenced by greeks and romans; Medievals: eaten fresh, dried and candied; stews

Dates: imported by Romans and Greeks; Medievals imported them dried from Arabic lands, eaten as-is or in sauces

Vegetables

Garlic: [Asia] evidenced by Egyptians, Greeks and Romans; Medievals: sauces; salads; preserved; medicines;

Onions: [Asia] evidenced by Eqyptians, Greeks and Romans; Medievals: salads, sauces, soups, stews

Cabbage: [Indigenous] evidenced by Eqyptians, Greeks and Romans; Medievals it is found as cabbage cultivars including cauliflower, kale, broccoli, etc; soups, stews, salads; pickled; cooked; juiced

Lettuce: [Indigenous] evidenced by Greeks and Romans; Medievals: salads

Turnips: [Indigenous] evidenced by Romans; Medievals: cooked; stews; pickled;

Parsnips: [Indigenous] evidenced by Greeks and Romans; Medievals: cooked; preserved; juiced for sweet essence

Carrots: [Indigenous] not cultivated as root for eating by Romans or Greeks, 'modern' carrot developed in the early middle ages in the south and became staple in the north by late middle ages (yellow or purple in colour); salads, stews

Beets: [Indigenous] evidenced by Romans; Medievals cultivated varietals into chard; eaten cooked, sauces, soups;

Radishes: [Indigenous] evidenced by Eqyptians, Greeks and Romans; Medievals eaten as salad, cooked, sauces, soups, stews;

Gourds: [Indigenous] evidenced by Romans; Medievals: soups, stews, cooked

Cucumbers: [India?] evidenced by Greeks and Romans; Medievals: soups, salads

Asparagus: [Indigenous] evidenced by Greeks and Romans; Medievals: cooked, fried

Eggplant (Aubergine): [India] Medievals: received from Arabs in early middle ages; cooked, fried;

Spinach: [Persia 4th CE] Medievals: received from Arabs in high middle ages, boiled, fried, salads

Mushrooms: [Indigenous] evidenced by Greeks and Romans; Medievals: cooked, fried, salads, dried

Olives: [Indigenous] evidenced by Greeks and Romans; medievals: pressed oils; preserved

Beyond fruits and vegetables, there were a lot of native herbs and wild leaf varietals ('salads') and a lot of nuts which, if not native to Europe, were established by the time of Greeks from eastern sources; nuts like almonds, walnuts, hazelnuts, pine nuts, pistachios, chestnuts. These would have all been present in medieval diets and are testified to in some surprising ways, including identification of almonds with heretics in the 13th century.