The first step is to solve the shopping list as cryptic clues to get the ingredients.

1: BUTTER
Definition = spread
around = reverse ( about = RE; two tablespoons = T T; gumbo evenly = U B )

2: RUM
Definition = liquor
fifth of cider = R; essence of cucumber = UM

3: FLAXMEAL
Definition = ground linseed
focaccia starter = F; easy = LAX; dinner = MEAL

4: TREACLE
Definition = thing that is too sweet
mixed = anagram ( CLEAR TEA without A )

5: FRUITS
et lit.
quarter figs = F; bananas = anagram ( skinned durio = URI ); cored tamarinds = TS

6: CINNAMON
Definition = spice
sodium enriched = NA inside ( vitamin = C; IN; 60% lemon = MON )

When you have identified all the ingredients, you are invited to a cooking class where you are given the ingredients, as well as a recipe:

Combine rum with:
first: bit of butter,
second: bit of flaxmeal,
third: bit of treacle,
with some cinnamon on top;
put it over fruits at the end
to get your desserts!

Following the recipe, as well as solving it as a cryptic, yields the final answer:

CRUMBLES
Definition: desserts
cinnamon on top = C; RUM; first bit of butter = B; second bit of flaxmeal = L; third bit of treacle = E; fruits at the end = S