Preheat oven (electric cooker: 225 °C/circulating air: 200 °C/gas: see manufacturer). Clean, wash and halve the fennel. Cut out the stalk in a wedge shape so that the fennel still holds together. Cut the fennel halves into thin slices.
Wash the sweet potatoes thoroughly and cut them into thin slices as well. Cut the garlic bulb with skin in half horizontally. Mix everything with oil and season with salt and pepper. Spread on a baking tray and bake in a hot oven for about 20 minutes.
In the meantime, mix cream cheese and milk for the dip. Finely crumble the crackers and stir into the dip. Season to taste with lemon juice, pepper and a little salt.
Wash the tomatoes and cut in half horizontally. Wash lemon hot, dry and cut into slices. Wash the thyme, shake dry and pluck the leaves. Put everything on the tray with the vegetables and bake for another 5 minutes.
Serve with the dip.