What kind of food was popular in London in the year 1775?

Answer 1

The late 17th century show the invention of the Muslim cloth, which helped cooks of the upper classes steam puddings faster than before. The English gained a strong appetite for puddings stuffed with any kind of meat.

Answer 2

Here's a good link to a website on English food from the 1700's.

To Roast a Hare.
Take your Hare when it is cas’d and make a Pudding; take a Quarter of a Pound of Sewet, and as much Crumbs of Bread, a little Parsley shred fine, and about as much Thyme as will lie on a Six-pence, when shred; an Anchovy shred small, a very little Pepper and Salt, some Nutmeg, two Eggs, a little Lemon-peel: Mix all this together, and put it into the Hare. Sew up the Belly, spit it, and lay it to the Fire, which must be a good one. Your Dripping-pan must be very clean and nice. Pour two Quarts of Milk and Half a Pound of Butter into the Pan; keep basting it all the while it is roasting with the Butter and Milk till the Whole is used, and your Hare will be enough. You may mix the Liver in the Pudding, if you like. You must first parboil it, then chop it fine.
[The Art of Cookery Made Plain and Easy, 1747]

The following recipes are from ‘The Country Housewife’s Companion’ (1750)

To bake the Ears, Feet, the Nose-part, Mugget, or gristly lean Parts of a Hock of Pork.
These, or any part of them, may be made a good family pleasant dish, thus: - Lay them in a glazed earthen pot, and strew over them some salt, pepper, onions, one or more bay leaves; over these pour water till it is above them, bake it two or three hours, and keep it as it comes out of the oven till wanted, then cut and fry it in slices; the sauce is a little of the pickle, flower, and butter melted with some mustard.

The Farmers Way of dressing a Porker's Head, Feet, and Ears.
We make no more to do, than to boil them tender, and eat them with mustard; and if any of them are left cold, we fry them in lard with some onions, and eat with mustard. - Or else, mince the flesh of them, and lade butter over it for eating. - But to eat the feet and ears in a nicer manner; when they are boiled, chop them small, and mix butter with gravey, shalot, mustard, and slices of lemon; then stew all together.

Take a large Bunch of Sellery, wash and pare it very clean, cut it into little Bits, and boil it softly in a little Water till it is tender; then add a little beaten Mace, some Nutmeg, Pepper and Salt, thicken’d with a good Piece of Butter roll’d in Flour, then boil it up, and pour into your dish. [The Art of Cookery Made Plain and Easy, 1747]

Pease Pudding.
Soak the peas for ten or twelve hours; tie them loosely in a cloth, leaving room for them to swell, and simmer for a couple of hours*. When tender, drain them; rub them through a colander with a wooden spoon; add an ounce of butter, one egg, beat up, and pepper and salt to taste. Beat them well together, tie lightly in a cloth, and boil for half an hour.

Hannah Glasse (1747) avoids any suggestion of ethnic slurring by giving recipes for Welch, Scotch AND English RABBITS.

To make a Scotch Rabbit.
Toast a piece of Bread very nicely on both Sides, butter it, cut a Slice of Cheese, about as big as the Bread, toast it on both Sides, and lay it on the Bread.

To make a Welch Rabbit.
Toast the Bread on both Sides, then toast the Cheese on one Side, lay it on the Toast, and with a hot Iron brown the other side. You may rub it over with Mustard.

To make an English Rabbit.
Toast a Slice of Bread brown on both sides, then lay it in a Plate before the Fire, pour a Glass of Red Wine over it, and let it soak the Wine up; then cut some Cheese very thin, and lay it very thick over the Bread; put it in a Tin Oven before the Fire, and it will be toasted and brown presently. Serve it away hot.

To make an Onion Soup.
Take a neck and Hough of Beef, a Nuckle of Veal, boil all the Substance out of the Meat, put in with them 3 or 4 Onions stuck with Cloves and a little black Pepper, Jamaica Pepper; when they are all well boiled, strain the Liquor thro’ a Callender, then take two Dozen of large Onionis, boil them in a little of the Broth; when they are well enough, pour off the Liquor they were boiled in, put the Onions into a Plate, and pour the Soup on them. “Mrs. McLintock’s Receipts for Cookery and Pastry-Work†(1736).

To make Wiggs.
You must take two Pounds of Flour, and a Quarter of a Pound of Butter, as much Sugar, a Nutmeg grated, a little Cloves and Mace, and a Quarter of an Ounce of Carraway Seeds, Cream and Yest [yeast] as much as will make it up into a light Paste, make them up, and set them by the Fire to rise ‘till the Oven be ready; they will quickly be baked.